code: def _create_model(self, view_getter=None, source_getters=None,
                        model_factory=None, officer=None):
          
  
          if view_getter is not None:
              d = defer.succeed(view_getter)
              d.addCallback(self._retrieve_view)
              d.addCallback(self._check_view)
          else:
              # views are inherited
              d = defer.succeed(self.model.view)
  
          d.addCallback(self._retrieve_model, source_getters,
                        model_factory, officer)
  
          d.addErrback(self._filter_errors)
          return d
docs: Creates a model from the model factory after retrieving
          the source and the view. The officer is the IOfficer
          FOR THE MODEL TO BE CREATED and NO OFFICER CHECKS ARE PERFORMED.