docs: def signal(self, container, instances=None, map_name=None, **kwargs):
          """
          Sends a signal to a single running container configuration (but possibly multiple instances). If not specified
          with ``signal``, this signal is ``SIGKILL``.
  
          :param container: Container configuration name.
          :type container: unicode | str
          :param map_name: Container map name.
          :type map_name: unicode | str
          :param instances: Instance name. Optional, if not specified sends the signal to all configured instances, or
            the default.
          :type instances: unicode | str
          :param kwargs: Keyword arguments to the script runner function.
          :return: Return values of actions.
          :rtype: list[dockermap.map.runner.ActionOutput]
          """
          return self.run_actions('signal', container, instances=instances, map_name=map_name, **kwargs)