code: func RetrieveallIPwhitelabels() {
  	apiKey := os.Getenv("SENDGRID_API_KEY")
  	host := "https://api.sendgrid.com"
  	request := sendgrid.GetRequest(apiKey, "/v3/whitelabel/ips", host)
  	request.Method = "GET"
  	queryParams := make(map[string]string)
  	queryParams["ip"] = "test_string"
  	queryParams["limit"] = "1"
  	queryParams["offset"] = "1"
  	request.QueryParams = queryParams
  	response, err := sendgrid.API(request)
  	if err != nil {
  		log.Println(err)
  	} else {
  		fmt.Println(response.StatusCode)
  		fmt.Println(response.Body)
  		fmt.Println(response.Headers)
  	}
  }
docs: // RetrieveallIPwhitelabels : Retrieve all IP whitelabels
  // GET /whitelabel/ips