function _checkDelExpect($error_code)
    {
        $deleted = false;
        foreach ($this->_expected_errors as $key => $error_array) {
            if (in_array($error_code, $error_array)) {
                unset($this->_expected_errors[$key][array_search($error_code, $error_array)]);
                $deleted = true;
            }

            // clean up empty arrays
            if (0 == count($this->_expected_errors[$key])) {
                unset($this->_expected_errors[$key]);
            }
        }

        return $deleted;
    }