code: def train(self, training_data: TrainingData) -> Resource:
      # Do something here with the messages
      return self._resource
  
file_path: rasa/data/test_classes/custom_graph_components/nlu_meta_fallback.py
imports: from typing import Dict, Text, Any, List
  from rasa.engine.graph import GraphComponent, ExecutionContext
  from rasa.engine.recipes.default_recipe import DefaultV1Recipe
  from rasa.engine.storage.resource import Resource
  from rasa.engine.storage.storage import ModelStorage
  from rasa.shared.nlu.training_data.message import Message
  from rasa.shared.nlu.training_data.training_data import TrainingData
  from rasa.nlu.classifiers.fallback_classifier import FallbackClassifier
label_desc: Use image node_id 3 for calling the MetaFallback obj's underlying member method code with example usage: obj.train(training_data) and returns: self