def _mul(a, b):
    """Multiplies two series objects
    (no validation since internally used).

    Parameters
    ----------

    a : Pandas ``Series``
        One of two Pandas ``Series`` objects that will
        be interacted together.

    b : Pandas ``Series``
        One of two Pandas ``Series`` objects that will
        be interacted together.


    Returns
    -------

    product np.ndarray
    """
    return (a * b).values