code: function(recognizer) {
          if (recognizer instanceof Recognizer) {
              return recognizer;
          }
  
          var recognizers = this.recognizers;
          for (var i = 0; i < recognizers.length; i++) {
              if (recognizers[i].options.event == recognizer) {
                  return recognizers[i];
              }
          }
          return null;
      }
docs: get a recognizer by its event name.
  @param {Recognizer|String} recognizer
  @returns {Recognizer|Null}