public static function has(string $name, string $namespace = '*'): bool
    {
        self::initialize();
        return isset($_SESSION[$namespace]) && array_key_exists($name, $_SESSION[$namespace]);
    }
public static function has(string $name, string $namespace = '*'): bool
    {
        self::initialize();
        return isset($_SESSION[$namespace]) && array_key_exists($name, $_SESSION[$namespace]);
    }
public static function has ( string $ name , string $ namespace = '*' ) : bool { self :: initialize ( ) ; return isset ( $ _SESSION [ $ namespace ] ) && array_key_exists ( $ name , $ _SESSION [ $ namespace ] ) ; }
Check if session-variable exists.

@param string $name
@param string $namespace Default '*'.
@return bool
Check if session - variable exists .