code: func NewDNSProviderCredentials(project string) (*DNSProvider, error) {
  	if project == "" {
  		return nil, fmt.Errorf("googlecloud: project name missing")
  	}
  
  	client, err := google.DefaultClient(context.Background(), dns.NdevClouddnsReadwriteScope)
  	if err != nil {
  		return nil, fmt.Errorf("googlecloud: unable to get Google Cloud client: %v", err)
  	}
  
  	config := NewDefaultConfig()
  	config.Project = project
  	config.HTTPClient = client
  
  	return NewDNSProviderConfig(config)
  }
docs: // NewDNSProviderCredentials uses the supplied credentials
  // to return a DNSProvider instance configured for Google Cloud DNS.