code: func (call *GetNumberMessagesCall) Do() (*MessagesNumberResponse, error) {
  	endpoint := fmt.Sprintf(APIEndpointGetMessageDelivery, call.deliveryType)
  	var q url.Values
  	if call.date != "" {
  		q = url.Values{"date": []string{call.date}}
  	}
  	res, err := call.c.get(call.ctx, endpoint, q)
  	if err != nil {
  		return nil, err
  	}
  	defer closeResponse(res)
  	return decodeToMessagesNumberResponse(res)
  }
docs: // Do method