def argmax(self, axis=None, skipna=True):
nv.validate_minmax_axis(axis)<EOL>return nanops.nanargmax(self._values, skipna=skipna)<EOL>
Return an ndarray of the maximum argument indexer.

Parameters
----------
axis : {None}
    Dummy argument for consistency with Series
skipna : bool, default True

See Also
--------
numpy.ndarray.argmax