flake8 is described as 'Flake8 is a wrapper around PyFlakes, pep8 and Ned Batchelder's McCabe script and displays the warnings in a per-file, merged output' and is an app in the Development category. There are five alternatives to flake8 for Mac, Windows, Linux and Python. The best alternative is PyLint, which is both free and Open Source. Other great apps like flake8 are PEP8 (Free, Open Source), PyFlakes (Free, Open Source), PyChecker (Free, Open Source) and PEP 257 (Free, Open Source).
pep257 is a static analysis tool for checking compliance with Python PEP 257. The framework for checking docstring style is flexible, and custom checks can be easily added, for example to cover NumPy docstring conventions.