          function subscribeFn(_event, _conf, _map, _bus) {
            var wayToListen = _conf.once ? '$once' : '$on';
            var fn = _conf.handler ? _conf.handler.bind(this) : _conf.bind(this);

            _map[_event]
              ? _map[_event].push(fn)
              : _map[_event] = [fn];
            _bus[wayToListen](_event, fn);
          }
