linear models, or models that have a linear component) and building design matrices. Patsy brings the convenience of R "formulas" to Python. https://github.com/pydata/patsy
for describing models in Python, regardless of the underlying package in use – just as formulas are the standard interface to all R packages. Therefore we’ve tried to make it as easy as possible for you to build Patsy support into your libraries. https://patsy.readthedocs.io/en/latest/library-developers.html
Probabilistic Machine Learning which focuses on advanced Markov chain Monte Carlo and variational fitting algorithms. Its flexibility and extensibility make it applicable to a large suite of problems. https://pymc-devs.github.io/pymc3/