Contao\Config::has PHP Method

    public static function has($strKey)
    {
        return array_key_exists($strKey, $GLOBALS['TL_CONFIG']);
    }

 /**
  * Checks whether a configuration value exists.
  *
  * @param string $key The short key
  *
  * @return bool True if the configuration value exists
  */
 public function has($key)
 {
     return Config::has($key);
 }