numpy.ndarray.putmask : Changes elements of an array
            based on conditional and input values.

        Examples
        --------
        >>> idx1 = pd.Index([1, 2, 3])
        >>> idx2 = pd.Index([5, 6, 7])
        >>> idx1.putmask([True, False, False], idx2)
        Index([5, 2, 3], dtype='int64')
        N)