def fromkeys(cls, iterable, *args):
            'Create a ChainMap with a single dict created from the iterable.'
            return cls(dict.fromkeys(iterable, *args))
Create a ChainMap with a single dict created from the iterable.
stackoverflow/venv/lib/python3.6/site-packages/pip-19.0.3-py3.6.egg/pip/_vendor/distlib/compat.py