code: def relatedItems(self):
          '''
          If this item is associated with a registration, then return all other items associated with
          the same registration.
          '''
          if self.registration:
              return self.registration.revenueitem_set.exclude(pk=self.pkf relatedItems(self):
          '''
          If this item is associated with a registration, then return all other items associated with
          the same registration.
          '''
          if self.registration:
              return self.registration.revenueitem_set.exclude(pk=self.pk)
docs: If this item is associated with a registration, then return all other items associated with
          the same registration.