code: def train(self, training_data: TrainingData) -> Resource:
      # TODO: Implement this if your component requires training
      ...
  
file_path: rasa/data/test_classes/nlu_component_skeleton.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
label_desc: Use image node_id 2 for calling the CustomNLUComponent obj's underlying member method code with example usage: obj.train(training_data) without return types