public function setConfig(array $config)
    {
        foreach ($config as $key => $value) {
            switch ($key) {
                case 'verbose':
                case 'loadEnv':
                    if (!is_bool($value)) {
                        throw new ConfigurationException($key, 'This should be a boolean value.');
                    }

                    $this->config[$key] = $value;
                    break;

                default:
                    throw new ConfigurationException($key, 'This is an unknown configuration option.');
            }
        }
    }