code: def duplicate(self):
          '''
          Returns a copy of the current group, including its lines.
          @returns: Group
          '''
          return self.__class__(amount=self.amount, date=self.date,
                                method=self.method, ref=self.reff duplicate(self):
          '''
          Returns a copy of the current group, including its lines.
          @returns: Group
          '''
          return self.__class__(amount=self.amount, date=self.date,
                                method=self.method, ref=self.ref)
docs: Returns a copy of the current group, including its lines.
          @returns: Group