phonenumbers.go
func (ipn *IncomingNumberService) BuyNumber(phoneNumber string) (*IncomingPhoneNumber, error) {
	data := url.Values{"PhoneNumber": []string{phoneNumber}}
	return ipn.NumberPurchasingService.Create(context.Background(), data)
}
func (ipn *IncomingNumberService) BuyNumber(phoneNumber string) (*IncomingPhoneNumber, error) {
	data := url.Values{"PhoneNumber": []string{phoneNumber}}
	return ipn.NumberPurchasingService.Create(context.Background(), data)
}
// BuyNumber attempts to buy the provided phoneNumber and returns it if
// successful.