check_admin_referer

	 * This function ensures the user intends to perform a given action, which helps protect against clickjacking style
	 * attacks. It verifies intent, not authorisation, therefore it does not verify the user's capabilities. This should
	 * be performed with `current_user_can()` or similar.
	 *
	 * If the nonce value is invalid, the function will exit with an "Are You Sure?" style message.
	 *
	 * @since 1.2.0
	 * @since 2.5.0 The `$query_arg` parameter was added.
	 *
	 * @param int|string $action    The nonce action.
	 * @param string     $query_arg Optional. Key to check for nonce in `$_REQUEST`. Default '_wpnonce'.
	 * @return int|false 1 if the nonce is valid and generated between 0-12 hours ago,
	 *                   2 if the nonce is valid and generated between 12-24 hours ago.
	 *                   False if the nonce is invalid.
	 */
	function check_admin_referer( $action = -1, $query_arg = '_wpnonce' ) {
		if ( -1 === $action ) {
			_doing_it_wrong( __FUNCTION__, __( 'You should specify a nonce action to be verified by using the first parameter.' ), '3.2.0' );
		}

		$adminurl = strtolower( admin_url() );
		$referer  = strtolower( wp_get_referer() );
		$result   = isset( $_REQUEST[ $query_arg ] ) ? wp_verify_nonce( $_REQUEST[ $query_arg ], $action ) : false;

		/**
		 * Fires once the admin request has been validated or not.
		 *