code: def handle_command(pymux, input_string):
      
      assert isinstance(input_string, six.text_type)
  
      input_string = input_string.strip()
      logger.info('handle command: %s %s.', input_string, type(input_string))
  
      if input_string and not input_string.startswith('#'):  # Ignore comments.
          try:
              if six.PY2:
                  # In Python2.6, shlex doesn't work with unicode input at all.
                  # In Python2.7, shlex tries to encode using ASCII.
                  parts = shlex.split(input_string.encode('utf-8'))
                  parts = [p.decode('utf-8') for p in parts]
              else:
                  parts = shlex.split(input_string)
          except ValueError as e:
              # E.g. missing closing quote.
              pymux.show_message('Invalid command %s: %s' % (input_string, e))
          else:
              call_command_handler(parts[0], pymux, parts[1:])
docs: Handle command.