code: function(events, handler) {
          if (events === undefined) {
              return;
          }
  
          var handlers = this.handlers;
          each(splitStr(events), function(event) {
              if (!handler) {
                  delete handlers[event];
              } else {
                  handlers[event] && handlers[event].splice(inArray(handlers[event], handler), 1);
              }
          });
          return this;
      }
docs: unbind event, leave emit blank to remove all handlers
  @param {String} events
  @param {Function} [handler]
  @returns {EventEmitter} this