docstr: Test _maybe_convert_to_wave_bytes works correctly when sample_rate
  is None.
docstr_tok: ["Test","_maybe_convert_to_wave_bytes","works","correctly","when","sample_rate","is","None","."]
code: def test_maybe_convert_to_wave_bytes_without_sample_rate(self):
      """Test _maybe_convert_to_wave_bytes works correctly when sample_rate
      is None."""
  
      np_arr = np.array([0, 1, 2, 3])
      computed_bytes = _maybe_convert_to_wav_bytes(
          np_arr, sample_rate=None
      )
      self.assertTrue(computed_bytes is np_arr)
  
imports: import io
  import os
  from io import BytesIO
  import numpy
  from parameterized import parameterized
  from scipy.io import wavfile
  import streamlit
  from streamlit.elements.media import _maybe_convert_to_wav_bytes
  from streamlit.errors import StreamlitAPIException
  from streamlit.proto.Alert_pb2 import Alert
  from streamlit.runtime.media_file_storage import MediaFileStorageError
  from streamlit.runtime.memory_media_file_storage import _calculate_file_id
  from streamlit.web.server.server import MEDIA_ENDPOINT
  from tests.delta_generator_test_case import DeltaGeneratorTestCase
label_desc: Use image node_id 10 for calling the AudioTest obj's underlying member method code with example usage: obj.test_maybe_convert_to_wave_bytes_without_sample_rate() without return types