Number Game Refinement issue: UnboundLocalError: local variable 'guess' referenced before assignment

When I enter a ValueError for my guess the programme spags out and gives me an error. I can't seem to find what the issue is. Can anyone help please?

This is my code:

import random

def game(): # generate a random number between 1 - 10 secret_num = random.randint(1, 10) guesses = []

while len(guesses) < 5:
    try:
        # get a number guess from the player
        guess = int(input("Guess a random number between 1 and 10. You have 5 attempts: "))
    except ValueError:
        print("{} isn't a number!".format(guess))
    else:
        # compare guess to secret number
        if guess == secret_num:
            print("You got it! My number was {}".format(secret_num))
            break
        elif guess < secret_num:
            print("My number is higher than {}.".format(guess))
        else:
            print("My number is lower than that.".format(guess))
        guesses.append(guess)
else:
    print("You didn't get it! My secret number was {}.".format(secret_num))
play_again = input("Do you want to play again? Y/n ")
if play_again.lower() != 'n':
    game()
else:
  print("Bye!") 

game()

The error I'm given is:

Guess a random number between 1 and 10. You have 5 attempts: f
Traceback (most recent call last):
File "number_game.py", line 11, in game
guess = int(input("Guess a random number between 1 and 10. You have 5 attempts: "))
ValueError: invalid literal for int() with base 10: 'f'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "number_game.py", line 32, in <module>
game()
File "number_game.py", line 13, in game
print("{} isn't a number!".format(guess))
UnboundLocalError: local variable 'guess' referenced before assignment