code: def _l_cv_weight_factor(self):
          
          b = 0.0047 * sqrt(0) + 0.0023 / 2
          c = 0.02609 / (self.catchment.record_length - 1)
          return c / (b + c)
docs: Return multiplier for L-CV weightings in case of enhanced single site analysis.
  
          Methodology source: Science Report SC050050, eqn. 6.15a and 6.15b