* description = @Translation("Create and store date values."),
* default_widget = "datetime_default",
* default_formatter = "datetime_default",
- * list_class = "\Drupal\datetime\Plugin\Field\FieldType\DateTimeFieldItemList"
+ * list_class = "\Drupal\datetime\Plugin\Field\FieldType\DateTimeFieldItemList",
+ * constraints = {"DateTimeFormat" = {}}
* )
*/
class DateTimeItem extends FieldItemBase {