Congrats to Openstack

openstack.php

<?php 
interface Congratulations
{
    public function congrats();
}

class OpenStack implements Congratulations 
{
    static $instance;

    public static function getAwesomeCloud( $classe = __CLASS__ )
    {
        if (!isset(self::$instance)) {
            self::$instance = new $classe;
        }
        return self::$instance;
    }

    private function __construct()
    {

    }

    public function congrats()
    {
        return 'Happy Birthday OpenStack';
    }
}


$OpenStack = OpenStack::getAwesomeCloud();
echo $OpenStack->congrats();