anchor.diff:          }
       }
   
  -    void removeListener(String event, Function listener) {
  +    EventEmitter removeListener(String event, Function listener) {
           if (_listeners.containsKey(event) && _listeners[event].contains(listener)) {
               _listeners[event].remove(listener);
           }
  
positive.code:                 _oneTimeListeners[event].clear();
              }
          }
      }
  
      void setMaxListeners(int listenersCount) {
          _maxListeners = listenersCount;
      }
  
      List listeners(String event) {
  
negative.code:     static int defaultMaxListeners = 10;
      int _maxListeners;
  
      EventEmitter addListener(String event, Function listener) {
          if (!_listeners.containsKey(event)) {
              _listeners[event] = [];
          }
  
          _verifyListenersLimit(event);
          _listeners[event].add(listener);
  
          return this;
      }
  
      EventEmitter on(String event, Function listener) {
          return addListener(event, listener);
      }
  
      EventEmitter once(String event, Function listener) {
          if (!_oneTimeListeners.containsKey(event)) {
              _oneTimeListeners[event] = [];
          }
  
          _verifyListenersLimit(event);
          _oneTimeListeners[event].add(listener);
  
          return this;
      }
  
      int _getMaxListeners() {
  