WC_Data::error PHP Method

When invalid data is found, throw an exception unless reading from the DB.

protected error ( string $error_code, string $error_message )
$error_code	string	Error code.
$error_message	string	Error message.

    protected function error($error_code, $error_message)
    {
        throw new WC_Data_Exception($error_code, $error_message);
    }

WC_Data