code: def _get_message(self, message, node):
      if message is None:
          message = self.message
          if message is None:
              raise ValueError("The message on the class is not set.")
      return message
  
imports: from contextlib import contextmanager
  from parso._compatibility import use_metaclass
label_desc: Use image node_id 4 for calling the Rule obj's underlying member method code with example usage: obj._get_message(message, node) and returns: message