code: func (c *Client) UpdateDNSRecord(sessionID, domainName string, records []DNSRecord) error {
  	payload := &Request{
  		Action: "updateDnsRecords",
  		Param: UpdateDNSRecordsRequest{
  			DomainName:      domainName,
  			CustomerNumber:  c.customerNumber,
  			APIKey:          c.apiKey,
  			APISessionID:    sessionID,
  			ClientRequestID: "",
  			DNSRecordSet:    DNSRecordSet{DNSRecords: records},
  		},
  	}
  
  	err := c.doRequest(payload, nil)
  	if err != nil {
  		return fmt.Errorf("error when sending the request: %v", err)
  	}
  
  	return nil
  }
docs: // UpdateDNSRecord performs an update of the DNSRecords as specified by the netcup WSDL
  // https://ccp.netcup.net/run/webservice/servers/endpoint.php