pandas.Series docstrings dtype information
docstring for pandas.Series states:

    dtype : numpy.dtype or None
        If None, dtype will be inferred

I'm new at this so I don't know all the dtypes that are valid, but at the very least I see that I can write dtype='category' yet categorical_dtype is (as far as I know) *not* a numpy.dtype (or am I missing something?)

Assuming I'm correct, that there is at least one (possibly more) valid input(s) for dtype that are NOT numpy.dtypes (and not None), then it would be nice if all of them could be listed here.  If someone can point me in the right direction (where to gather valid dtype inputs) I would be happy to make the docstring change myself and enter a PR. 