<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_mean(self, C, rup, dists, sites):
 """ Returns the mean value of ground motion - noting that in this case the style-of-faulting term is neglected """

        return (self._get_magnitude_scaling_term(C, rup.mag) +
                self._get_distance_scaling_term(C, dists.rjb, rup.mag) +
                self._get_site_amplification_term(C, sites.vs30))