protected function processConfig(ConfigInterface $config)
    {
        if (func_num_args() > 1) {
            try {
                $keys = func_get_args();
                array_shift($keys);
                $config = $config->getSubConfig($keys);
            } catch (Exception $exception) {
                throw new FailedToProcessConfigException(
                    sprintf(
                        _('Could not process the config with the arguments "%1$s".'),
                        print_r(func_get_args(), true)
                    )
                );
            }
        }
        $this->config = $config;
    }