public add_meta ( integer $level_id, string $meta_key = '', mixed $meta_value, boolean $unique = false ) : boolean | ||
$level_id | integer | Subscription level ID. |
$meta_key | string | Metadata name. |
$meta_value | mixed | Metadata value. |
$unique | boolean | Optional, default is false. Whether the same key should not be added. |
return | boolean | False for failure. True for success. |