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Type Hints

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José Padilla

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Work Training

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Work Open Source

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PEP 3107

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PEP 484

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no type checking happens at runtime

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static analysis refactoring runtime type checking code generation

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static analysis refactoring runtime type checking code generation

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Common built-in types

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Generics

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mypy

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static type checker

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$ pip install mypy

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$ python app.py

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$ python app.py f 1 Traceback (most recent call last): File "app.py", line 12, in print(first(1)) # TypeError File "app.py", line 7, in first return seq[0] TypeError: 'int' object is not subscriptable

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$ mypy app.py

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$ mypy app.py main.py:12: error: Argument 1 to "first" has incompatible type "int"; expected "Sequence[]"

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mypy-lang.org

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Python will remain a dynamically typed language

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Thanks! jpadilla.com twitter.com/@jpadilla_ github.com/jpadilla