lues are treated as if they had the value fill_value.

Parameters
----------
axis : {None, integer}
    If None, the index is into the flattened array, otherwise along
    the specified axis
fill_value : scalar or None, optional
    Value used to fill in the masked values.  If None, the output of
    maximum_fill_value(self._data) is used instead.
out : {None, array}, optional
    Array into which the result can be placed. Its type is preserved
    and it must be of the right shape to hold the output.

Returns
-------
index_array : {integer_array}

Examples
--------
>>> import numpy as np
>>> a = np.arange(6).reshape(2,3)
>>> a.argmax()
5
>>> a.argmax(0)
array([1, 1, 1])
>>> a.argmax(1)
array([2, 2])

Fr`