Online PHP editor | refs for uhTDQ

<?php $_SESSION['MAster'] = '4632763278'; unset($_SESSION['MAster']); if($_SESSION['MAster']){ echo 'HELLO'; } if(in_array($_SESSION,'MAster')){ echo 'HELLO'; } if(isset($_SESSION['MAster'])){ echo 'HELLO 2'; } if($_SESSION['MAster']=='4632763278'){ echo 'HELLO 3'; }