code: func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
  	if config == nil {
  		return nil, errors.New("gandi: the configuration of the DNS provider is nil")
  	}
  
  	if config.APIKey == "" {
  		return nil, fmt.Errorf("gandi: no API Key given")
  	}
  
  	if config.BaseURL == "" {
  		config.BaseURL = defaultBaseURL
  	}
  
  	return &DNSProvider{
  		config:              config,
  		inProgressFQDNs:     make(map[string]inProgressInfo),
  		inProgressAuthZones: make(map[string]struct{}),
  		findZoneByFqdn:      dns01.FindZoneByFqdn,
  	}, nil
  }
docs: // NewDNSProviderConfig return a DNSProvider instance configured for Gandi.