code: def load_modules(self):
          
          if self.INTERFACES_MODULE is None:
              raise NotImplementedError("A module containing interfaces modules "
                                        "should be setup in INTERFACES_MODULE !")
          else:
              for module, permission in self.modules.items():
                  i = getattr(self.INTERFACES_MODULE,
                              module).Interface(self, permission)
                  self.interfaces[module] = i
docs: Should instance interfaces and set them to interface, following `modules`