code: def setup_callables(self):
          
          defaults = self.get_default_callables()
          for key, value in list(defaults.items()):
              self._postponed_callables.setdefault(key, value)
          for key in self.callables:
              value = self._postponed_callables.pop(key)
              value.setup_callable_system(self.system, init=True)
              setattr(self, key, value)
docs: Setup Callable attributes that belong to this object.