That's not really an specific question about an specific problem, but I'd like to know how to improve this code, because I think that the main_func is just too big and I can not split it into other functions or classes. Also I want to know if I can or should use classes to make it cleaner. It's a simple HANGMAN game.

import random
import string


def starting():
    print('HANGMAN')
    print('Set game mode:')
    print('0. To exit')
    print('1. Easy')
    print('2. Medium')
    print('3. Hard')
    difficult = int(input('Your choice: '))
    if difficult == 1:
        difficult_easy()
    elif difficult == 2:
        difficult_medium()
    elif difficult == 3:
        difficult_hard()

    else:
        exit('Exiting...')


def main_func(word_lst, guesses_given):

    secret_word = random.choice(word_lst)
    output = []
    guessed_letters = []
    alphabet = string.ascii_letters
    length = len(secret_word)
    print(f'Your word has {len(secret_word)} characters ')

    for i in range(len(secret_word)):
        output.append('_')

    while '_' in output:

        letter = input('Enter a letter: ')

        if letter not in alphabet:
            print('You should enter only one letter!\n ')
        elif len(letter) != 1:
            print('You can only display 1 letter at a time\n')
        else:
            if letter not in guessed_letters:
                guessed_letters.append(letter)

                if letter in secret_word:
                    for n in range(length):
                        if secret_word[n] == letter:
                            output[n] = letter.upper()
                    print(*output, sep=' ')
                    if '_' not in output:
                        print('You won!')

                if letter not in secret_word:
                    guesses_given -= 1
                    print(f"This letter is not in the secret word. REMAINING TRIES: {guesses_given}\n")
                    if guesses_given == 0:
                        print(f"You lost. The secret word was '{secret_word.upper()}'")
                        break

            else:
                print('You have already guessed this letter!\n\n')



    print('GAMEOVER')
    play_again()



def play_again():
    again = input('Play again? (y/n)\n')
    if again.lower() == 'yes' or again.lower() == 'y':
        starting()
    else:
        exit('Exiting...')


def difficult_easy():
    main_func(['hall', 'exam', 'road', 'gate', 'debt', 'poet', 'sir', 'girl', 'food'], 14)


def difficult_medium():
    main_func(['customer', 'baseball', 'language', 'stranger', 'quantity',
               'judgment', 'republic', 'proposal', 'magazine'], 12)


def difficult_hard():
    main_func(['assumption', 'impression', 'restaurant', 'indication', 'excitement',
               'depression', 'government', 'inspection', 'protection', 'investment'], 10)


if __name__ == '__main__':
    starting()

For me it looks garbage, but I did my best to make it simple and short at the same time. I want to use classes to make it more simple, but i still hadn't figured out... The last thing I want to ask is about the if __name__ == '__main__':, am I using it correctly?

Could any one help me pls?

I posted it on stackoverflow but people said that the site is only for specific problems in your code, so they told me to go here