docs: def get(cls, action, suffix=None):
          """
          Get or register a handler for the given action.
  
          :param func action: Callback that is called when invoking the Handler
          :param func suffix: Optional suffix for the handler's ID
          """
          action_id = _action_id(action, suffix)
          if action_id not in cls._HANDLERS:
              if LOG_OPTS['register']:
                  hookenv.log('Registering reactive handler for %s' % _short_action_id(action, suffix),
                              level=hookenv.DEBUG)
              cls._HANDLERS[action_id] = cls(action, suffix)
          return cls._HANDLERS[action_id]