def _get_magnitude_term(self, C, mag):
        """
        Returns the magnitude scaling term.
        """
        lny = C['C1'] + (C['C3'] * ((8.5 - mag) ** 2.))
        if mag > 6.3:
            return lny + (-C['H'] * C['C5']) * (mag - 6.3)
        else:
            return lny + C['C2'] * (mag - 6.3)
Returns the magnitude scaling term.