class registered_user extends dikiy implements usersFace {
....
$usertype='registered_user';
$user=new $usertype();

class fabric {
	public function newuserstr($usertype){
		$user=new $usertype();
		return newuser($user);
	}
}

class fabric {
	public function newuserstr($usertype){
		$user=new $usertype();
		return newuser($user);
	}
}

class fabric {
	public  function newuser(usersFace $u){
		return $u;
	}
}