PROBLEM: When creating account: It should be 6 digit pin. (if there is a letter or not 6 digits were put in, output will say "Please retry. It should be a 6 digit pin."). It should also have an authenticator for the pin and if the inputted pin is wrong show "Invalid Pin. Please try again." and if it is still wrong in 3 tries, it'll say "Too many incorrect tries. Exiting program."    CODE:    import random import sys   class ATM():     def __init__(customer, name, account_number, balance = 0):         customer.name = name         customer.account_number = account_number         customer.balance = balance               def account_detail(customer):         print("\n-ACCOUNT DETAIL-")         print(f"Account Holder: {customer.name.upper()}")         print(f"Account Number: {customer.account_number}")         print(f"Available balance: Nu.{customer.balance}\n")               def deposit(customer, amount):         customer.amount = amount         customer.balance = customer.balance + customer.amount         if amount >= 8000:             print("Your balance is Above PHP 8000")         print("Current account balance: ₱", customer.balance)       def withdraw(customer, amount):         customer.amount = amount         if customer.amount > customer.balance:             print("Insufficient fund!")             print(f"Your balance is PHP{customer.balance} only.")             print("Try with lesser amount than balance.")             print()         else:             customer.balance = customer.balance - customer.amount             print(f"Nu.{amount} withdrawal successful!")             if customer.balance < 8000:                 print("Your balance is Below PHP 8000")             print("Current account balance: ₱", customer.balance)             print()       def check_balance(customer):         if customer.balance >= 8000:             print("Your balance is Above PHP 8000")         else:             print("Your balance is Below PHP 8000")         print("Available balance: ₱", customer.balance)         print()         def transaction(customer):         print("""             TRANSACTION         *********************             Menu:             1. Account Detail             2. Check Balance             3. Deposit             4. Withdraw             5. Exit         *********************         """)                 while True:             try:                 option = int(input("Enter 1, 2, 3, 4 or 5:"))             except:                 print("Error: Enter 1, 2, 3, 4, or 5 only.\n")                 continue             else:                 if option == 1:                     atm.account_detail()                 elif option == 2:                         atm.check_balance()                 elif option == 3:                     amount = int(input("How much you want to deposit(₱.):"))                     atm.deposit(amount)                 elif option == 4:                     amount = int(input("How much you want to withdraw(₱.):"))                     atm.withdraw(amount)                 elif option == 5:                     print(f"""                 printing receipt..............           ************************************************************           |   • Transaction is now complete.            |   • Transaction number: {random.randint(10000, 1000000)}            |   • Account holder: {customer.name.upper()}              |   • Account number: {customer.account_number}             |   • Available balance: ₱.{customer.balance}            |                |   Thanks for choosing us as your bank ☺                        ************************************************************           """)                     sys.exit()                     print("""         |=================== Welcome Customer! ==================|         |==============- Automated Teller Machine -===========|         """) print("----------ACCOUNT CREATION----------") name = input("Enter your name: ") account_number = input("Enter your account number: ") print("Congratulations! Account created successfully......\n")   atm = ATM(name, account_number)   while True:     print("|-------------TRANSACTION-------------|")     trans = input("Do you want to do any transaction?(yes/no):")     if trans == "yes":         atm.transaction()     elif trans == "no":         print("""     -------------------------------------    | Thanks for choosing us as your bank     | Visit us again!        -------------------------------------         """)         break     else:         print("Wrong command!  'Enter yes' or 'no'.\n")