code: def _vec_lnqmed_residuals(self, catchments):
          
          result = np.empty(len(catchments))
          for index, donor in enumerate(catchments):
              result[index] = self._lnqmed_residual(donor)
          return result
docs: Return ln(QMED) model errors for a list of catchments
  
          :param catchments: List of gauged catchments
          :type catchments: list of :class:`Catchment`
          :return: Model errors
          :rtype: list of float