public function isError($obj)
    {
        // is it even an object?
        if (! is_object($obj)) { // if not an object, can't even be a SavantPHPerror object
            return false;
        } else {
            // now compare the parentage
            $is = $obj instanceof SavantPHPerror;
            $sub = is_subclass_of($obj, 'SavantPHPerror');
            return ($is || $sub);
        }
    }