             self.entityDescriptionValues = {
                 (
                     attributeType: .undefinedAttributeType,
-                    isOptional: isOptional,
+                    isOptional: true,
                     isTransient: true,
                     allowsExternalBinaryDataStorage: false,
                     versionHashModifier: nil,


        fileprivate init(
            keyPath: KeyPathString,
            isOptional: Bool,
            customGetter: ((_ object: ObjectProxy<O>, _ field: ObjectProxy<O>.FieldProxy<V>) -> V)?,
            customSetter: ((_ object: ObjectProxy<O>, _ field: ObjectProxy<O>.FieldProxy<V>, _ newValue: V) -> Void)? ,
            affectedByKeyPaths: @escaping () -> Set<KeyPathString>) {


        self.init(
            keyPath: keyPath,
            customGetter: customGetter,
            customSetter: customSetter,
            affectedByKeyPaths: affectedByKeyPaths
