WordPress at a glance
function is not described

WP_Network::__isset() public WP 4.6.0

Isset-er.

Allows current multisite naming conventions when checking for properties.

{} It's a method of the class: WP_Network{}

No Hooks.

Return

true|false. Whether the property is set.

Usage

$WP_Network = new WP_Network();
$WP_Network->__isset( $key );
$key(string) (required)
Property to check if set.

Changelog

Since 4.6.0 Introduced.

Code of WP_Network::__isset() WP 5.7

<?php
public function __isset( $key ) {
	switch ( $key ) {
		case 'id':
		case 'blog_id':
		case 'site_id':
			return true;
	}

	return false;
}