code: def _compute_magnitude_scaling_term(self, C, mag):
          
          c1 = self.CONSTS['c1']
          if mag <= c1:
              return C['b1'] + C['b2'] * (mag - c1) + C['b3'] * (8.5 - mag) ** 2
          else:
              return C['b1'] + C['b7'] * (mag - c1) + C['b3'] * (8.5 - mag) ** 2
docs: Compute and return magnitude scaling term in equation 2,
          page 970.