code: func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
  	if config == nil {
  		return nil, errors.New("cloudflare: the configuration of the DNS provider is nil")
  	}
  
  	if config.TTL < minTTL {
  		return nil, fmt.Errorf("cloudflare: invalid TTL, TTL (%d) must be greater than %d", config.TTL, minTTL)
  	}
  
  	client, err := cloudflare.New(config.AuthKey, config.AuthEmail, cloudflare.HTTPClient(config.HTTPClient))
  	if err != nil {
  		return nil, err
  	}
  
  	return &DNSProvider{client: client, config: config}, nil
  }
docs: // NewDNSProviderConfig return a DNSProvider instance configured for Cloudflare.