Simple Hangman Game

import random
secret_words = ["attempt"], ["August"], ["Autumn"], ["border"], ["breeze"], ["brick"], ["calm"], ["canal"], ["Casey"], ["cast"], ["chose"], ["claws"], ["coach"], ["constantly"], ["contrast"], ["cookies"], ["customs"], ["damage"], ["Danny"], ["deeply"], ["depth"], ["discussion"], ["doll"], ["donkey"], ["Egypt"], ["Ellen"], ["essential"], ["exchange"], ["exist"], ["explanation"], ["facing"], ["film"], ["finest"], ["fireplace"], ["floating"], ["folks"], ["fort"], ["garage"], ["grabbed"], ["grandmother"], ["habit"], ["happily"], ["Harry"], ["heading"], ["hunter"], ["Illinois"], ["image"], ["independent"], ["instant"], ["January"], ["kids"], ["label"], ["Lee"], ["lungs"], ["manufacturing"], ["Martin"], ["mathematics"], ["melted"], ["memory"], ["mill"], ["mission"], ["monkey"], ["Mount"], ["mysterious"], ["neighborhood"], ["Norway"], ["nuts"], ["occasionally"], ["official"], ["ourselves"], ["palace"], ["Pennsylvania"], ["Philadelphia"], ["plates"], ["poetry"], ["policeman"], ["positive"], ["possibly"], ["practical"], ["pride"], ["promised"], ["recall"], ["relationship"], ["remarkable"], ["require"], ["rhyme"], ["rocky"], ["rubbed"], ["rush"], ["sale"], ["satellites"], ["satisfied"], ["scared"], ["selection"], ["shake"], ["shaking"], ["shallow"], ["shout"], ["silly"], ["simplest"], ["slight"], ["slip"], ["slope"], ["soap"], ["solar"], ["species"], ["spin"], ["stiff"], ["swung"], ["tales"], ["thumb"], ["tobacco"], ["toy"], ["trap"], ["treated"], ["tune"], ["University"], ["vapor"], ["vessels"], ["wealth"], ["wolf"], ["zoo"]

answer = str(random.choice(secret_words))
answer = answer.strip("[']")
answer = answer.lower()
answer_length = len(answer)
progress = len(answer) * [" "]
guesses = 0
letters_used = ""

def progress_updater(guess,answer,progress):
    i = 0
    while i < len(answer):
        if guess == answer[i]:
            progress[i] = guess
            i +=1
        else:
            i +=1
    return "".join(progress)

def gui(guesses):
    if guesses == 0:
        print("________      ")
        print("|             ")
        print("|             ")
        print("|             ")
        print("|             ")
        print("|             ")
    elif guesses == 1:
        print("________      ")
        print("|      |      ")
        print("|             ")
        print("|             ")
        print("|             ")
        print("|             ")
    elif guesses == 2:
        print("________      ")
        print("|      |      ")
        print("|      0      ")
        print("|             ")
        print("|             ")
        print("|             ")
    elif guesses == 3:
        print("________      ")
        print("|      |      ")
        print("|      0      ")
        print("|     /       ")
        print("|             ")
        print("|             ")
    elif guesses == 4:
        print("________      ")
        print("|      |      ")
        print("|      0      ")
        print("|     /|      ")
        print("|             ")
        print("|             ")
    elif guesses == 5:
        print("________      ")
        print("|      |      ")
        print("|      0      ")
        print("|     /|\     ")
        print("|             ")
        print("|             ")
    elif guesses == 6:
        print("________      ")
        print("|      |      ")
        print("|      0      ")
        print("|     /|\     ")
        print("|     /       ")
        print("|             ")
    else:
        print("________      ")
        print("|      |      ")
        print("|      0      ")
        print("|     /|\     ")
        print("|     / \     ")
        print("|             ")
        print("GAME OVER!")
        print("The word was:",answer)
        input("press enter to exit\n>")
        exit()

while True:
    if " " not in progress:
        print(progress)
        print("Congratz you won!")
        print("The word was:", answer)
        break
    print("letters used:",letters_used)
    print(progress,"\n")

    guess = input("Please only enter a single letter\n> ").lower()
    letters_used = letters_used+guess

    if guess not in answer:
        print("Uh-oh You guessed wrong! \n")
        guesses+=1
        print("you have",7-guesses,"guesses left")
        gui(guesses=guesses)

    if len(guess) == 1:
        if guess in answer:
            print("Correct! you guessed:", guess)
            progress_updater(guess=guess, answer=answer, progress=progress)
            gui(guesses=guesses)