class A {
  public class __call($name, $params) {
     if (method_exists?($this, $name)) {
       $result = call_user_func_array([$this, $name], $params);
       return $result;
     }
  }
}

class B {
  private function hello() {
    echo "Hello"
  }
}

$b = new B();
$b->hello();