Argument 'fastpath' in 'Categorical' not documented
In documentaion for `pandas.Categorical`:
https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.Categorical.html

Argument `fastpath` which can be passed to the class constructor is not documented on the docstring:
https://github.com/pandas-dev/pandas/blob/master/pandas/core/arrays/categorical.py