SystemMeta.php
<?php
namespace PressForward\Interfaces;
interface SystemMeta {
public function add_meta( $post_id, $meta_key, $meta_value, $unique);
public function update_meta( $post_id, $meta_key, $meta_value, $prev_value);
public function delete_meta( $post_id, $meta_key, $meta_value);
public function get_meta( $post_id, $key = '', $single = false );
}