code: func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
  	if config == nil {
  		return nil, errors.New("dnsimple: the configuration of the DNS provider is nil")
  	}
  
  	if config.AccessToken == "" {
  		return nil, fmt.Errorf("dnsimple: OAuth token is missing")
  	}
  
  	ts := oauth2.StaticTokenSource(&oauth2.Token{AccessToken: config.AccessToken})
  	client := dnsimple.NewClient(oauth2.NewClient(context.Background(), ts))
  
  	if config.BaseURL != "" {
  		client.BaseURL = config.BaseURL
  	}
  
  	return &DNSProvider{client: client, config: config}, nil
  }
docs: // NewDNSProviderConfig return a DNSProvider instance configured for DNSimple.