Essence\Di\Container::unique PHP Метод

    public static function unique(Closure $closure)
    {
        return function ($Container) use($closure) {
            static $result = null;
            if ($result === null) {
                $result = $closure($Container);
            }
            return $result;
        };
    }

 /**
  *
  */
 public function testGetUnique()
 {
     $unique = Container::unique(function ($Container) {
         return new Containable();
     });
     $first = $unique($this->Container);
     $second = $unique($this->Container);
     $this->assertSame($first, $second);
 }