code: func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
  	if config == nil {
  		return nil, errors.New("hostingde: the configuration of the DNS provider is nil")
  	}
  
  	if config.APIKey == "" {
  		return nil, errors.New("hostingde: API key missing")
  	}
  
  	if config.ZoneName == "" {
  		return nil, errors.New("hostingde: Zone Name missing")
  	}
  
  	return &DNSProvider{
  		config:    config,
  		recordIDs: make(map[string]string),
  	}, nil
  }
docs: // NewDNSProviderConfig return a DNSProvider instance configured for hosting.de.