所以下面的代碼給出了一個輸入，檢查輸入是否是一個字符長，在過去的猜測中，看看它是否是一個字母。否則它應該返回消息再試一次。但是，在嘗試代碼時，我只得到 else 條件而無法得到 if 條件（應該返回結果）。任何人都知道為什么以及如何解決這個問題？def get_guess(past_guesses):"""Checks if past_guesses is 1 letter, a letter or has been used before, and prompts user to try againExample:>>> get_guess(['A', 'a', 'c', 'd'])'You need to enter one alphabetic character which you haven't\already guessed. Try again'>>> get_guess(['a', 'b', 'c', 'd'])'a'"""answer = "'You need to enter one alphabetic character which you haven't\already guessed. Try again'"while True:    guess = input("Guess a letter: ")    if guess.isalpha() and len(guess) == 1 and guess not in past_guesses:        past_guesses.append(guess)        return guess    else:        print (answer)