code: def test_multilingual_forward(self):
      num_speakers = 10
      num_langs = 3
      batch_size = 2
  
      args = VitsArgs(
          language_ids_file=LANG_FILE,
          use_language_embedding=True,
          spec_segment_size=10,
      )
      config = VitsConfig(
          num_speakers=num_speakers,
          use_speaker_embedding=True,
          model_args=args,
      )
  
      (
          input_dummy,
          input_lengths,
          _,
          spec,
          spec_lengths,
          waveform,
      ) = self._create_inputs(config, batch_size=batch_size)
      speaker_ids = (
          torch.randint(0, num_speakers, (batch_size,))
          .long()
          .to(device)
      )
      lang_ids = (
          torch.randint(0, num_langs, (batch_size,)).long().to(device)
      )
  
      model = Vits(config).to(device)
      output_dict = model.forward(
          input_dummy,
          input_lengths,
          spec,
          spec_lengths,
          waveform,
          aux_input={
              "speaker_ids": speaker_ids,
              "language_ids": lang_ids,
          },
      )
      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 12 for calling the TestVits obj's underlying member method code with example usage: obj.test_multilingual_forward() without return types