code: func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
  	if config == nil {
  		return nil, errors.New("dyn: the configuration of the DNS provider is nil")
  	}
  
  	if config.CustomerName == "" || config.UserName == "" || config.Password == "" {
  		return nil, fmt.Errorf("dyn: credentials missing")
  	}
  
  	return &DNSProvider{config: config}, nil
  }
docs: // NewDNSProviderConfig return a DNSProvider instance configured for Dyn DNS