docs: function (val, model) {
              var name = this.name;
              if (!isUndefinedOrNull(val)) {
                  this.__setValue(model, this._toModel(val));
              } else if (!model.isNew && isNull(val)) {
                  model.__isChanged = true;
                  this.__setValue(model, this._toModel(val));
                  model[this.removeAssociationFlagName] = true;
              }
          }