parse_str issue in php 8.1 - error on empty $request->get('variable')

ErrorException: parse_str(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/.../vendor/workerman/workerman/Protocols/Http/Request.php:446
Stack trace:
#0 [internal function]: {closure}(8192, 'parse_str(): Pa...', '/var/www/...', 446)
#1 /var/www/.../vendor/workerman/workerman/Protocols/Http/Request.php(446): parse_str(NULL, Array)
#2 /var/www/.../vendor/workerman/workerman/Protocols/Http/Request.php(111): Workerman\Protocols\Http\Request->parseGet()
#3 /var/www/.../app/controller/list_fonts.php(24): Workerman\Protocols\Http\Request->get('f')
#4 /var/www/.../vendor/workerman/webman-framework/src/App.php(253): app\controller\list_fonts->category(Object(support\Request), 'miscellaneous-f...')
#5 /var/www/.../vendor/workerman/webman-framework/src/App.php(146): Webman\App::Webman\{closure}(Object(support\Request))
#6 /var/www/.../vendor/workerman/workerman/Connection/TcpConnection.php(638): Webman\App->onMessage(Object(Workerman\Connection\TcpConnection), Object(support\Request))
#7 [internal function]: Workerman\Connection\TcpConnection->baseRead(Resource id #236, 2, Resource id #236)
#8 /var/www/.../vendor/workerman/workerman/Events/Event.php(193): EventBase->loop()
#9 /var/www/.../vendor/workerman/workerman/Worker.php(2418): Workerman\Events\Event->loop()
#10 /var/www/.../vendor/workerman/workerman/Worker.php(1542): Workerman\Worker->run()
#11 /var/www/.../vendor/workerman/workerman/Worker.php(1373): Workerman\Worker::forkOneWorkerForLinux(Object(Workerman\Worker))
#12 /var/www/.../vendor/workerman/workerman/Worker.php(1347): Workerman\Worker::forkWorkersForLinux()
#13 /var/www/.../vendor/workerman/workerman/Worker.php(542): Workerman\Worker::forkWorkers()
#14 /var/www/.../start.php(156): Workerman\Worker::runAll()
#15 {main}