code: def test_forward(self):
      num_speakers = 0
      config = VitsConfig(
          num_speakers=num_speakers, use_speaker_embedding=True
      )
      config.model_args.spec_segment_size = 10
      (
          input_dummy,
          input_lengths,
          _,
          spec,
          spec_lengths,
          waveform,
      ) = self._create_inputs(config)
      model = Vits(config).to(device)
      output_dict = model.forward(
          input_dummy, input_lengths, spec, spec_lengths, waveform
      )
      self._check_forward_outputs(config, output_dict)
  
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 9 for calling the TestVits obj's underlying member method code with example usage: obj.test_forward() without return types