docs: function (key, value) {
          var accessor = getAccessors(this)[key],
              oldVal = this.get(key);
  
  
          this.triggerBeforeChanged(key, oldVal);
  
          if (accessor) {
              accessor.target.set(accessor.key, value);
          } else {
  
              if (this['set_' + key]) {
                  this['set_' + key](value);
              } else {
                  this[key] = value;
              }
          }
          this.triggerChanged(key, oldVal);
      }