code: def test_deferred_loading_model_and_unload(self):
      model_id = 0
      opt = {"models": ["test_model.pt"]}
      model_root = TEST_DIR
      sm = ServerModel(opt, model_id, model_root=model_root, load=False)
      self.assertFalse(sm.loaded)
      sm.load()
      self.assertTrue(sm.loaded)
      self.assertIsInstance(sm.translator, Translator)
      sm.unload()
      self.assertFalse(sm.loaded)
  
imports: import unittest
  from onmt.translate.translation_server import ServerModel, TranslationServer
  import os
  from textwrap import dedent
  import torch
  from onmt.translate.translator import Translator
label_desc: Use image node_id 1 for calling the TestServerModel obj's underlying member method code with example usage: obj.test_deferred_loading_model_and_unload() without return types