func (cli *OpsGenieHeartbeatClient) Add(req heartbeat.AddHeartbeatRequest) (*heartbeat.AddHeartbeatResponse, error) {
	req.ApiKey = cli.apiKey
	// validate mandatory fields: apiKey, name
	if req.ApiKey == "" {
		return nil, errors.New("Api Key is a mandatory field and can not be empty")
	}
	if req.Name == "" {
		return nil, errors.New("Heart beat name is a mandatory field and can not be empty")
	}
	// send the request
	resp, err := cli.buildRequest("POST", ADD_HEARTBEAT_URL, req).Do()
	// resp, err := goreq.Request{ Method: "POST", Uri: ADD_HEARTBEAT_URL, Body: req, }.Do()
	if err != nil {
		return nil, errors.New("Can not add a new heart beat, unable to send the request")
	}
	// check for the returning http status, 4xx: client errors, 5xx: server errors
	statusCode := resp.StatusCode
	if statusCode >= 400 && statusCode < 500 {
		return nil, errors.New(fmt.Sprintf("Client error %d occured", statusCode))
	}
	if statusCode >= 500 {
		return nil, errors.New(fmt.Sprintf("Server error %d occured", statusCode))
	}
	// try to parse the returning JSON into the response
	var addHeartbeatResp heartbeat.AddHeartbeatResponse
	if err = resp.Body.FromJsonTo(&addHeartbeatResp); err != nil {
		return nil, errors.New("Server response can not be parsed")
	}
	// parsed successfuly with no errors
	return &addHeartbeatResp, nil
}
// Add method creates a heartbeat at OpsGenie.
func (cli *OpsGenieHeartbeatClient) Add(req heartbeat.AddHeartbeatRequest) (*heartbeat.AddHeartbeatResponse, error) {
	req.APIKey = cli.apiKey

	resp, err := cli.sendRequest(cli.buildPostRequest(addHeartbeatURL, req))

	if resp == nil {
		return nil, err
	}
	defer resp.Body.Close()

	var addHeartbeatResp heartbeat.AddHeartbeatResponse
	if err = resp.Body.FromJsonTo(&addHeartbeatResp); err != nil {
		message := "Server response can not be parsed, " + err.Error()
		logging.Logger().Warn(message)
		return nil, errors.New(message)
	}

	return &addHeartbeatResp, nil
}