code: public function has(string $name) : bool
      {
          $path = explode('.', $name);
          $key = $path[0];
  
          if (!isset($this->cache[$key])) {
              $file = $this->configFile($key);
  
              if (!file_exists($file)) {
                  return false;
              }
  
              $this->cache[$key] = new ConfigHelper($this->readConfig($file));
          }
  
          return $this->cache[$key]->has($path);
      }
docs: {@inheritdoc}