WP_Users_List_Table::__construct( array $args = array() )

	public function __construct( $args = array() ) {
		parent::__construct( array(
			'singular' => 'user',
			'plural'   => 'users',
			'screen'   => isset( $args['screen'] ) ? $args['screen'] : null,
		) );

		$this->is_site_users = 'site-users-network' === $this->screen->id;

		if ( $this->is_site_users )
			$this->site_id = isset( $_REQUEST['id'] ) ? intval( $_REQUEST['id'] ) : 0;
	}