Python's default arguments are evaluated at definition as opposed to when the function is invoked. This leads to unexpected behavior, as mutations persist between calls. For a more detailed explanation, see The Hitchhiker's Guide to Python.

def fnc(a, b={}):
    pass

foo.py:2:14: M511 - mutable default arg of type Dict

pip install flake8-mutable

• Callables

• added MANIFEST.in

MIT