telegram bot apiv5. need inditificate command in caption under photo.

[aboguz]

if (update.Message.Photo.IsCommand() == "answer" && update.Message.Chat.ID == supportChatID){
handleAnswerCommand(bot, supportChatID, update.Message, update.Message.Photo[len(update.Message.Photo)-1].FileID, update.Message.Caption)
}
answer - command in tech channel which taking 3 arguments and writing like "/answer 1 <any text/text+photo>
that's why i cant write only "/answer" or:

if update.Message.IsCommand() {
switch update.Message.Command() {
case "answer": //that case doing well without photo. but with - program can't see that case
handleAnswerCommand(...)
}
}