code: function(eventName, handler) {
      if (!this.__eventListeners) {
        this.__eventListeners = { };
      }
      if (this.__eventListeners[eventName]) {
        fabric.util.removeFromArray(this.__eventListeners[eventName], handler);
      }
    }
docs: Stops event observing for a particular event handler
  @method stopObserving
  @depracated Since 0.8.34. Use `off` instead.
  @param {String} eventName
  @param {Function} handler