code: func NewDNSProvider() (*DNSProvider, error) {
  	values, err := env.Get(apiBaseEnvVar, storagePathEnvVar)
  	if err != nil {
  		return nil, fmt.Errorf("acme-dns: %v", err)
  	}
  
  	client := goacmedns.NewClient(values[apiBaseEnvVar])
  	storage := goacmedns.NewFileStorage(values[storagePathEnvVar], 0600)
  	return NewDNSProviderClient(client, storage)
  }
docs: // NewDNSProvider creates an ACME-DNS provider using file based account storage.
  // Its configuration is loaded from the environment by reading apiBaseEnvVar and storagePathEnvVar.