docstr: st.audio(None) is not an error.
docstr_tok: ["st.audio","(","None",")","is","not","an","error","."]
code: def test_st_audio_from_none(self):
      """st.audio(None) is not an error."""
      st.audio(None)
      el = self.get_delta_from_queue().new_element
      self.assertEqual(el.audio.url, "")
  
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 14 for calling the AudioTest obj's underlying member method code with example usage: obj.test_st_audio_from_none() without return types