protected function loadCustomServices($configDir) {
        if (!is_string($configDir)) throw new IllegalTypeException('Illegal type of parameter $configDir: '.gettype($configDir));
        if (!is_file($file = $configDir.'/services.php'))
            return false;

        foreach (include($file) as $name => $definition) {
            $this->set($name, $definition);
        }
        return true;
    }