code: def __check_classes(self):
          
          # msg took from BaseAuthentication
          msg = (
              "Sanic JWT was not initialized properly. It did not received "
              "an instance of {}"
          )
          if not issubclass(self.authentication_class, Authentication):
              raise exceptions.InitializationFailure(
                  message=msg.format("Authentication")
              )
  
          if not issubclass(self.configuration_class, Configuration):
              raise exceptions.InitializationFailure(
                  message=msg.format("Configuration")
              )
  
          if not issubclass(self.responses_class, Responses):
              raise exceptions.InitializationFailure(
                  message=msg.format("Responses")
              )
docs: Check if any of the default classes (`Authentication`, `Configuration`
          and / or `Responses`) have been overwitten and if they're still valid