code: def remove(self, value, session=None):
          '''Remove *value*, an instance of ``self.model`` from the set of
  elements contained by the field.'''
          s, instance = self.session_instance('remove', value, session)
          # update state so that the instance does look persistent
          instance.get_state(iid=instance.pkvalue(), action='update')
          return s.delete(instancef remove(self, value, session=None):
          '''Remove *value*, an instance of ``self.model`` from the set of
  elements contained by the field.'''
          s, instance = self.session_instance('remove', value, session)
          # update state so that the instance does look persistent
          instance.get_state(iid=instance.pkvalue(), action='update')
          return s.delete(instance)
docs: Remove *value*, an instance of ``self.model`` from the set of
  elements contained by the field.