code: func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
  	if config == nil {
  		return nil, errors.New("zoneee: the configuration of the DNS provider is nil")
  	}
  
  	if config.Username == "" {
  		return nil, fmt.Errorf("zoneee: credentials missing: username")
  	}
  
  	if config.APIKey == "" {
  		return nil, fmt.Errorf("zoneee: credentials missing: API key")
  	}
  
  	if config.Endpoint == nil {
  		return nil, errors.New("zoneee: the endpoint is missing")
  	}
  
  	return &DNSProvider{config: config}, nil
  }
docs: // NewDNSProviderConfig return a DNSProvider .