code: def call_command_handler(command, pymux, arguments):
      
      assert isinstance(arguments, list)
  
      # Resolve aliases.
      command = ALIASES.get(command, command)
  
      try:
          handler = COMMANDS_TO_HANDLERS[command]
      except KeyError:
          pymux.show_message('Invalid command: %s' % (command,))
      else:
          try:
              handler(pymux, arguments)
          except CommandException as e:
              pymux.show_message(e.message)
docs: Execute command.
  
      :param arguments: List of options.