Improving your code without losing your mind

Most of us programmers focus too much on delivering features.

While this is clearly important, reserving some of your time to improve your code will pay off significantly.

In this talk at PyTexas 2023, I explain why you should refactor your code and provide practical tools for Python developers since most refactoring resources are not written for us.

Transcript

1. everyday
   superpowers
   Improving your code
   
   
   Without losing your mind
   Chris May—April 1, 2023
   

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2. everyday
   superpowers
   Improving your code
   
   
   Without losing your mind
   Chris May—April 1, 2023
   

   View Slide

3. everyday
   superpowers Source: https://blog.alexewerlof.com/p/tech-debt-day
   

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4. everyday
   superpowers
   —Alex Ewerlöf https://blog.alexewerlof.com/p/tech-debt-day
   “My struggles started from day one. I could not make
   sense of the code base and felt frustrated. At the
   time, I had 19 years of programming experience.
   
   
   …a simple task would take me multiple days longer
   than I thought…
   

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5. everyday
   superpowers
   —Alex Ewerlöf https://blog.alexewerlof.com/p/tech-debt-day
   “My struggles started from day one. I could not make
   sense of the code base and felt frustrated. At the
   time, I had 19 years of programming experience.
   
   
   …a simple task would take me multiple days longer
   than I thought. I felt dumb and helpless.”
   

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6. everyday
   superpowers
   —Alex Ewerlöf https://blog.alexewerlof.com/p/tech-debt-day
   “Leadership did not care about the code quality
   as long as the stories were delivered on time.
   Corners were cut, and tests were skipped.”
   

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7. everyday
   superpowers
   What did they do?
   • The team had an honest conversation about the problem.
   
   
   • Developers argued to stop developing new features to clean everything.
   
   
   • Project management (rightly) pushed back.
   
   
   • They negotiated to reserve every other Friday to reduce tech debt.
   

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8. everyday
   superpowers
   —Alex Ewerlöf https://blog.alexewerlof.com/p/tech-debt-day
   “Initially it was hard to defend spending
   10% of the team bandwidth on [cleaning
   our code]…
   

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9. everyday
   superpowers
   —Alex Ewerlöf https://blog.alexewerlof.com/p/tech-debt-day
   “Initially it was hard to defend spending
   10% of the team bandwidth on [cleaning
   our code], but the payback was huge.”
   

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10. everyday
    superpowers
    Refactoring results at 10%
    • the code quality improved
    • delivered features faster
    
    
    • nearly all "embarrassingly unnecessary incidents” eliminated
    
    
    • enabled them to make better judgment calls when we had to cut
    corners due to the time constraints
    
    
    • enjoyed their daily work more
    
    
    • inspired other teams to do the same
    

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11. everyday
    superpowers
    Most of us are too focused on
    

    getting features out the door.
    

    Regularly taking even a small percentage
    of your time to improve your code can
    reap huge benefits.
    

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12. everyday
    superpowers
    Agenda
    • Intro to refactoring
    
    
    • Two kinds of refactoring
    
    
    • Example
    
    
    • Why you should refactor
    
    
    • Resources
    

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13. everyday
    superpowers
    Hi, I’m Chris May!
    Python technical coach
    I help python developers and teams reach
    their potential by temporarily joining teams
    and improving how they build software.
    
    
    https://everydaysuperpowers.dev
    

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14. everyday
    superpowers
    What is
    refactoring?
    

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15. everyday
    superpowers
    Refactoring:
    
    
    Improving code without changing
    its behavior
    Refactor
    

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16. everyday
    superpowers
    We Refactor to:
    
    
    • Make code understandable
    
    
    • Support new directions
    Refactor
    

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17. everyday
    superpowers
    Top-Down vs
    
    
    Bottom-Up
    

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18. everyday
    superpowers
    Top-down
    • Were written with less-
    fl
    exible
    languages in mind
    
    
    • Are “destinations” you can take your
    code to
    

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19. everyday
    superpowers
    Over 60 refactoring methods
    • Change Function Declaration
    
    
    • Change Reference to Value
    
    
    • Change Value to Reference
    
    
    • Collapse Hierarchy
    
    
    • Combine Functions into Class
    
    
    • Combine Functions into
    Transform
    
    
    • Consolidate Conditional
    Expression
    
    
    • Decompose Conditional
    
    
    • Encapsulate Collection
    
    
    • Encapsulate Record
    
    
    • Encapsulate Variable
    
    
    • Extract Class
    
    
    • Extract Function
    
    
    • Extract Superclass
    
    
    • Extract Variable
    
    
    • Hide Delegate
    
    
    • Inline Class
    
    
    • Inline Function
    
    
    • Inline Variable
    
    
    • Introduce Assertion
    
    
    • Introduce Parameter Object
    
    
    • Introduce Special Case
    
    
    • Move Field
    
    
    • Move Function
    
    
    • Move Statements into Function
    
    
    • Move Statements to Callers
    
    
    • Parameterize Function
    
    
    • Preserve Whole Object
    
    
    • Pull Up Constructor Body
    
    
    • Pull Up Field
    
    
    • Pull Up Method
    
    
    • Push Down Field
    
    
    • Push Down Method
    
    
    • Remove Dead Code
    
    
    • Remove Flag Argument
    
    
    • Remove Middle Man
    
    
    • Remove Setting Method
    
    
    • Remove Subclass
    
    
    • Rename Field
    
    
    • Rename Variable
    
    
    • Replace Command with Function
    
    
    • Replace Conditional
    

    with Polymorphism
    
    
    • Replace Constructor with
    

    Factory Function
    
    
    • Replace Control Flag with Break
    
    
    • Replace Derived Variable with Query
    
    
    • Replace Error Code with Exception
    
    
    • Replace Exception with Precheck
    
    
    • Replace Function with Command
    
    
    • Replace Inline Code with
    

    Function Call
    
    
    • Replace Loop with Pipeline
    
    
    • Replace Magic Literal
    
    
    • Replace Nested Conditional
    with Guard Clauses
    
    
    • Replace Parameter with Query
    
    
    • Replace Primitive with Object
    
    
    • Replace Query with Parameter
    
    
    • Replace Subclass with Delegate
    
    
    • Replace Superclass with
    Delegate
    
    
    • Replace Temp with Query
    
    
    • Replace Type Code with
    Subclasses
    
    
    • Return Modi
    fi
    ed Value
    
    
    • Separate Query from Modi
    fi
    er
    
    
    • Slide Statements
    
    
    • Split Loop
    
    
    • Split Phase
    
    
    • Split Variable
    
    
    • Substitute Algorithm
    

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20. everyday
    superpowers
    Top-down refactoring boiled down
    1. Ensure tests cover what you want to change.
    
    
    2. Duplicate the implementation.
    
    
    3. Adjust the code as necessary to cover all cases, running tests every time
    you make a change.
    
    
    4. Reroute original code to new code, one instance at a time, and run tests.
    
    
    5. Remove old implementation.
    
    
    6. Test again.
    

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21. everyday
    superpowers
    Refactoring styles
    Top-down
    • Were written with less-
    fl
    exible
    languages in mind
    
    
    • Are “destinations” you can take your
    code to
    Bottom-up
    • Starts with your code
    
    
    • A series of small steps allow good
    

    design patterns to emerge
    

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22. everyday
    superpowers
    Refactoring styles
    Bottom-up
    • Starts with your code
    
    
    • A series of small steps allow good
    

    design patterns to emerge
    

    View Slide

23. everyday
    superpowers
    The Flocking
    Rules
    

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24. everyday
    superpowers
    from textwrap import dedent
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

25. everyday
    superpowers
    from textwrap import dedent
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

26. everyday
    superpowers
    from textwrap import dedent
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

27. everyday
    superpowers
    from textwrap import dedent
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

28. everyday
    superpowers
    from textwrap import dedent
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

29. everyday
    superpowers
    from textwrap import dedent
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

30. everyday
    superpowers
    from textwrap import dedent
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    verse ???
    1 `
    fi
    rst`
    2 `second`
    3 `third`
    

    View Slide

31. everyday
    superpowers
    from textwrap import dedent
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    verse Nth
    1 `
    fi
    rst`
    2 `second`
    3 `third`
    

    View Slide

32. everyday
    superpowers
    from textwrap import dedent
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

33. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    pass
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

34. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    pass
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

35. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

36. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

37. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent("""\
    
    
    On the first day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

38. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

39. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

40. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

41. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

42. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth():
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

43. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

44. everyday
    superpowers
    Tests Failed!
    

    View Slide

45. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

46. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number = 1):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

47. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number = 1):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent("""\
    
    
    On the second day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

48. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number = 1):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

49. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number = 1):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

50. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number = 1):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

51. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number = 1):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth()} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

52. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number = 1):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

53. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number = 1):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

54. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number = 1):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

55. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

56. everyday
    superpowers
    from textwrap import dedent
    
    
    def nth(number):
    
    
    if number == 2:
    
    
    return 'second'
    
    
    return 'first'
    
    
    def recite(verse: int) -> str:
    
    
    if verse == 2:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    two Turtle Doves,
    
    
    and a Partridge in a Pear Tree.
    
    
    """)
    
    
    else:
    
    
    return dedent(f"""\
    
    
    On the {nth(verse)} day of Christmas
    
    
    my true love gave to me:
    
    
    a Partridge in a Pear Tree.
    
    
    """)
    
    
    1.Identify what to work on
    
    1.Find the things that are most alike
    
    2.Identify the smallest di
    ff
    erence
    between them
    
    2.Make them identical.
    
    1.Create a component to resolve the
    variations.
    
    2.Implement code to supply one
    variation.
    
    3.Replace one of the di
    ff
    erences with
    a call to the component.
    
    4.Delete any unused code
    
    5.Repeat until the di
    ff
    erences are
    eliminated
    

    View Slide

57. everyday
    superpowers
    Inspiration
    

    View Slide

58. everyday
    superpowers
    —Brett Slatkin (author, Principal Software Engineer at Google) @ PyConUS 2016
    “Great programmers [write code that] makes
    

    so much sense… it's so easy to understand.”
    
    
    “[Most stop] at the point where [their code] works functionally.
    

    A great programmer continues on and refactors the
    

    code base so that it's easy to understand and the code 

    is obvious.”
    
    
    “They do this because it provides a better foundation for the
    future... Over the long run, it saves you time.”
    

    View Slide

59. everyday
    superpowers
    @app.get("/prices")
    
    
    async def compute_price(
    
    
    type: str,
    
    
    age: Optional[int] = None,
    
    
    date: Optional[datetime.date] = None,
    
    
    ):
    
    
    result = await database.fetch_one(
    
    
    select(base_price_table.c.cost)
    
    
    .where(base_price_table.c.type == type),
    
    
    )
    
    
    if age and age < 6:
    
    
    return {"cost": 0}
    
    
    else:
    
    
    if type != 'night':
    
    
    holidays = await database.fetch_all(select(holidays_table))
    
    
    is_holiday = False
    
    
    reduction = 0
    
    
    for row in holidays:
    
    
    if date:
    
    
    if date == row.holiday:
    
    
    is_holiday = True
    
    
    if not is_holiday and date and date.weekday() == 0:
    
    
    reduction = 35
    
    
    # TODO apply reduction for others
    
    
    if age and age < 15:
    
    
    
    

    View Slide

60. everyday
    superpowers
    if date:
    
    
    if date == row.holiday:
    
    
    is_holiday = True
    
    
    if not is_holiday and date and date.weekday() == 0:
    
    
    reduction = 35
    
    
    # TODO apply reduction for others
    
    
    if age and age < 15:
    
    
    return {"cost": math.ceil(result.cost * .7)}
    
    
    else:
    
    
    if not age:
    
    
    cost = result.cost * (1 - reduction / 100)
    
    
    return {"cost": math.ceil(cost)}
    
    
    else:
    
    
    if age > 64:
    
    
    cost = result.cost * .75 * (1 - reduction / 100)
    
    
    return {"cost": math.ceil(cost)}
    
    
    else:
    
    
    cost = result.cost * (1 - reduction / 100)
    
    
    return {"cost": math.ceil(cost)}
    
    
    else:
    
    
    if age and age >= 6:
    
    
    if age and age > 64:
    
    
    return {"cost": math.ceil(result.cost * .4)}
    
    
    else:
    
    
    return result
    
    
    else:
    
    
    return {"cost": 0}
    
    
    

    View Slide

61. everyday
    superpowers
    @app.get("/prices")
    
    
    async def compute_price(
    
    
    type: str,
    
    
    age: Optional[int] = None,
    
    
    date: Optional[datetime.date] = None,
    
    
    ):
    
    
    result = await database.fetch_one(
    
    
    select(base_price_table.c.cost)
    
    
    .where(base_price_table.c.type == type),
    
    
    )
    
    
    if age and age < 6:
    
    
    return {"cost": 0}
    
    
    else:
    
    
    if type != 'night':
    
    
    holidays = await database.fetch_all(select(holidays_table))
    
    
    is_holiday = False
    
    
    reduction = 0
    
    
    for row in holidays:
    
    
    if date:
    
    
    if date == row.holiday:
    
    
    is_holiday = True
    
    
    if not is_holiday and date and date.weekday() == 0:
    
    
    reduction = 35
    
    
    # TODO apply reduction for others
    
    
    if age and age < 15:
    
    
    
    

    View Slide

62. everyday
    superpowers
    async def compute_price(
    
    
    type: str, age: int = AGE_MISSING, date: datetime.date = DATE_MISSING
    
    
    ) -> int:
    
    
    if type == 'night':
    
    
    return await NightTicket(age).price
    
    
    return await NormalTicket(age, date).price
    
    
    
    
    class Ticket:
    
    
    ticket_kind = ''
    
    
    async def get_base_price(self):
    
    
    return await get_base_price_for(self.ticket_kind)
    
    
    class NightTicket(Ticket):
    
    
    ticket_kind = 'night'
    
    
    def __init__(self, age: int = AGE_MISSING, date: datetime = DATE_MISSING):
    
    
    self.age = age
    
    
    @property
    
    
    async def price(self):
    
    
    if self.age <= 6:
    
    
    return 0
    
    
    if self.age > 64:
    
    
    return math.ceil(await self.get_base_price() * .4)
    
    
    return await self.get_base_price()
    
    
    
    
    

    View Slide

63. everyday
    superpowers
    if self.age <= 6:
    
    
    return 0
    
    
    if self.age > 64:
    
    
    return math.ceil(await self.get_base_price() * .4)
    
    
    return await self.get_base_price()
    
    
    class NormalTicket(Ticket):
    
    
    ticket_kind = '1day'
    
    
    def __init__(self, age: int = AGE_MISSING, date: datetime.date = DATE_MISSING):
    
    
    self.age = age
    
    
    self.date = date
    
    
    @property
    
    
    async def price(self):
    
    
    if self.age <= 6:
    
    
    return 0
    
    
    if self.age < 15:
    
    
    return math.ceil(await self.get_base_price() * .7)
    
    
    reduction = 1 - 35 / 100 if await self.is_holiday() else 1
    
    
    if self.age > 64:
    
    
    return math.ceil(await self.get_base_price() * .75 * reduction)
    
    
    return math.ceil(await self.get_base_price() * reduction)
    
    
    async def is_holiday(self):
    
    
    holidays = {row.holiday for row in
    
    
    await database.fetch_all(select(holidays_table))}
    
    
    return self.date in holidays
    
    
    

    View Slide

64. everyday
    superpowers
    async def compute_price(
    
    
    type: str, age: int = AGE_MISSING, date: datetime.date = DATE_MISSING
    
    
    ) -> int:
    
    
    if type == 'night':
    
    
    return await NightTicket(age).price
    
    
    return await NormalTicket(age, date).price
    
    
    
    
    class Ticket:
    
    
    ticket_kind = ''
    
    
    async def get_base_price(self):
    
    
    return await get_base_price_for(self.ticket_kind)
    
    
    class NightTicket(Ticket):
    
    
    ticket_kind = 'night'
    
    
    def __init__(self, age: int = AGE_MISSING, date: datetime = DATE_MISSING):
    
    
    self.age = age
    
    
    @property
    
    
    async def price(self):
    
    
    if self.age <= 6:
    
    
    return 0
    
    
    if self.age > 64:
    
    
    return math.ceil(await self.get_base_price() * .4)
    
    
    return await self.get_base_price()
    
    
    
    
    

    View Slide

65. everyday
    superpowers
    async def compute_price(
    
    
    kind: str,
    
    
    age: int = AGE_MISSING,
    
    
    date: datetime.date = DATE_MISSING,
    
    
    ):
    
    
    base_price = await get_base_price(kind)
    
    
    if kind == 'night':
    
    
    if age < 6:
    
    
    return 0
    
    
    if 64 < age:
    
    
    return math.ceil(base_price * .4)
    
    
    return base_price
    
    
    else:
    
    
    if age < 6:
    
    
    return 0
    
    
    if age < 15:
    
    
    return math.ceil(base_price * .7)
    
    
    price_with_date_discount = (
    
    
    base_price * await _calculate_date_discount(date)
    
    
    )
    
    
    if 64 < age:
    
    
    return math.ceil(
    
    
    price_with_date_discount * 0.75
    
    
    )
    
    
    else:
    
    
    return math.ceil(price_with_date_discount)
    

    View Slide

66. everyday
    superpowers
    —Brett Slatkin (author, Principal Software Engineer at Google) @ PyConUS 2016
    “Great programmers [write code that] makes
    

    so much sense… it's so easy to understand.”
    
    
    “[Most stop] at the point where [their code] works functionally.
    

    A great programmer continues on and refactors the
    

    code base so that it's easy to understand and the code 

    is obvious.”
    
    
    “They do this because it provides a better foundation for the
    future... Over the long run, it saves you time.”
    

    View Slide

67. everyday
    superpowers
    Source: https://pyvideo.org/pycon-us-2016/brett-slatkin-refactoring-python-why-and-how-to-restructure-your-code-pycon-2016.html
    

    View Slide

68. everyday
    superpowers
    —Hynek Schlawack (creator of attrs and other elegant things)
    “I don’t really think of refactoring as a
    separate thing.
    
    
    It’s just the result of having tests and
    thinking about the design of your code
    all the time.”
    

    View Slide

69. everyday
    superpowers
    Source: https://thebent.co/the-ruthless-edit/
    

    View Slide

70. everyday
    superpowers
    Refactoring results at 10%
    • the code quality improved
    • delivered features faster
    
    
    • nearly all "embarrassingly unnecessary incidents” eliminated
    
    
    • enabled them to make better judgment calls when we had to cut
    corners due to the time constraints
    
    
    • enjoyed their daily work more
    
    
    • inspired other teams to do the same
    

    View Slide

71. everyday
    superpowers
    Refactoring results at 10%
    • the code quality improved
    • delivered features faster
    
    
    • nearly all "embarrassingly unnecessary incidents” eliminated
    
    
    • enabled them to make better judgment calls when we had to cut
    corners due to the time constraints
    
    
    • enjoyed their daily work more
    
    
    • inspired other teams to do the same
    

    View Slide

72. everyday
    superpowers
    How to learn to refactor
    • Ask a Python meetup to do a refactoring night.
    
    
    • Talk to your teammates about it.
    
    
    • Read through a code smell or refactoring method for
    

    10 minutes each week.
    
    
    • Practice often.
    

    View Slide

73. everyday
    superpowers
    Resources
    

    View Slide

74. everyday
    superpowers
    https://everydaysuperpowers.dev/toolkit/
    

    View Slide

75. everyday
    superpowers
    Connect
    https://everydaysuperpowers.dev/
    @_chrismay
    
    fosstodon.org/@_chrismay
    

    View Slide

76. everyday
    superpowers
    

    View Slide