docs: def send_message(message, pipe='public'):
      """
      writes message to pipe
      """
      if pipe not in ['public', 'private']:
          raise ValueError('pipe argument can be only "public" or "private"')
      else:
          pipe = pipe.upper()
  
      pipe_path = PUBLIC_PIPE if pipe == 'PUBLIC' else PRIVATE_PIPE
  
      # create file if it doesn't exist, append contents
      pipeout = open(pipe_path, 'a')
  
      pipeout.write('%s\n' % message)
      pipeout.close()