code: def test_get_criterion(self):
      config = VitsConfig(VitsArgs(num_chars=32))
      model = Vits.init_from_config(config, verbose=False).to(device)
      criterion = model.get_criterion()
      self.assertTrue(criterion is not None)
  
imports: import copy
  import os
  import unittest
  import torch
  from trainer.logging.tensorboard_logger import TensorboardLogger
  from tests import assertHasAttr, assertHasNotAttr, get_tests_data_path, get_tests_input_path, get_tests_output_path
  from TTS.config import load_config
  from TTS.encoder.utils.generic_utils import setup_encoder_model
  from TTS.tts.configs.vits_config import VitsConfig
  from TTS.tts.models.vits import Vits, VitsArgs, VitsAudioConfig, amp_to_db, db_to_amp, load_audio, spec_to_mel, wav_to_mel, wav_to_spec
  from TTS.tts.utils.speakers import SpeakerManager
label_desc: Use image node_id 27 for calling the TestVits obj's underlying member method code with example usage: obj.test_get_criterion() without return types