code: def compute_discounts(self, precision=None):
          '''
          Returns the total discounts of this group.
          @param precision: int Number of decimals
          @return: Decimal
          '''
          return sum([group.compute_discounts(precision) for group
                      in self.__groups]f compute_discounts(self, precision=None):
          '''
          Returns the total discounts of this group.
          @param precision: int Number of decimals
          @return: Decimal
          '''
          return sum([group.compute_discounts(precision) for group
                      in self.__groups])
docs: Returns the total discounts of this group.
          @param precision: int Number of decimals
          @return: Decimal