code: function(record) {
  
  		if (Lava.schema.DEBUG && !(record.guid in this._properties_by_guid)) Lava.t("isLess: record does not belong to this module");
  		var ref_record_a = this._properties_by_guid[record.guid][this._name];
  		// must return undefined, cause comparison against nulls behaves differently
  		return ref_record_a ? ref_record_a.get('id') : void 0;
  
  	}
docs: Get field's value equivalent for comparison
  @param {Lava.data.Record} record
  @returns {string}