code: def add_to_stream(audio, instream):
      time.sleep(1)
      if audio is None:
          return gr.Audio(), instream
      if instream is None:
          ret = audio
      else:
          ret = (audio[0], np.concatenate((instream[1], audio[1])))
      return ret, ret
  
label_desc: Use image node_id 1 for calling a global function with example usage: add_to_stream(audio, instream) and returns: ret,  ret, gr,  instream