Letterman game dosent work

import random
random_words = ["surface", "awesome", "keyboard", "mouse", "castle"]
while True:
    start = input("Press enter to start, or Q to quit")
    if start.lower() == "Q":
        break
    secret_word = random.choice(random_words)
    wrong_guesses = []
    right_guesses = []
    while len(wrong_guesses) < 10 and len(right_guesses) != len(list(secret_word)):
        for letter in secret_word:
            if letter in right_guesses:
                print(letter, end="")
            else:
                print("_", end="")
        print("")
        print("Strikes: {}/7".format(len(wrong_guesses)))
        print("")
        guess = input("Guess a letter: ").lower()
        if len(guess) != 1:
            print("Your can only guess a single letter!")
            continue
        elif guess in wrong_guesses or guess in right_guesses:
            print("You have already guessed that")
        elif not guess_isalpha():
            print("You can only guess letter!")
            continue
        if guess in secret_word:
            right_guesses.append(guess)
            if len(right_guesses) == len(list(secret_word)):
                print("You win! The word was {}".format(secret_word))
                break
        else:
            wrong_guesses.append(guess)
else:
    print("You didnt guess it! My secret word was {}".format(secret_word))