docs: function (key, target, targetKey, noNotify) {
          targetKey = targetKey || key;
          var self = this;
          this.unbind(key);
  
          var oldVal = this.get(key);
  
          // When bound property changes, trigger a 'changed' event on this one too
          getBindings(this)[key] = events.addListener(target, targetKey.toLowerCase() + '_changed', function (oldVal) {
              self.triggerChanged(key, oldVal);
          });
  
          addAccessor(this, key, target, targetKey, noNotify);
      }