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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _compute_mean(self, C, mag, ztor, rrup):
 """ Compute mean value as in ``subroutine getGeom`` in ``hazgridXnga2.f`` """

        gc0 = 0.2418
        ci = 0.3846
        gch = 0.00607
        g4 = 1.7818
        ge = 0.554
        gm = 1.414

        mean = (
            gc0 + ci + ztor * gch + C['gc1'] +
            gm * mag + C['gc2'] * (10 - mag) ** 3 +
            C['gc3'] * np.log(rrup + g4 * np.exp(ge * mag))
        )

        return mean