code: def invalidate(self, container):
          '''
          :param container: the container that tries to invalidate the condition
          '''
          self._get_ready(container)
          field_name = self._field.get_name()
          if field_name is None:
              raise KittyException('Cannot invalidate field without name')
          self._field_name = field_name
          self._field = Nonf invalidate(self, container):
          '''
          :param container: the container that tries to invalidate the condition
          '''
          self._get_ready(container)
          field_name = self._field.get_name()
          if field_name is None:
              raise KittyException('Cannot invalidate field without name')
          self._field_name = field_name
          self._field = None
docs: :param container: the container that tries to invalidate the condition