atm.py

from datetime import datetime
date=datetime.today()
date=date.strftime('%Y/%B/%d %H:%M:%S %p')

users={'1111':'user1','2222':'user2','3333':'user3','4444':'user4'}
user_amt={'1111':1000,'2222':2000,'3333':3000,'4444':4000}

print('Welcome to Py Bank!')
trial=0
while trial<=3:
    pin=input('\nEnter your atm pin:')
    if pin.isdigit()==True and len(pin)==4 and pin in users.keys():
        print('Hello!',users[pin],'\nLog in Successful!')
        break
    else:
        print('Invalid Input.\nTry again.')
        trial+=1
else:
    print('Four attempts failed.\nThis card has been blocked.')
    exit()

def get_acct_statement():
    print('\nDear',users[pin],'\nAccount balance as at',date,':','N',user_amt[pin])

def withdrawal():
    attempt=0
    while attempt<=3:
        amt=int(input("\nEnter amount to withdraw:"))
        if amt<200 or amt>user_amt[pin]:
            print("Withdrawal failed!\nYou can't withdraw lower than N200 or higher than your available balance.\nYour current balance is:N",user_amt[pin])
            attempt+=1
        else:
            print("Withdrawal Successful!\nPlease wait and collect you cash.")
            break
    else:
        print('Four attempts failed.\nTry again later.')
        exit()

def deposit():
    attempt=0
    while attempt<=3:
        amt=int(input('\nEnter amount to deposit:'))
        if amt<1000 or amt>100000:
            print("Deposit failed!\nYou can't deposit less than N1000 or more than N100000.")
            attempt+=1
        else:
            total=amt+user_amt[pin]
            print('Deposit Successful.\nYour new balance as at:',date,':N',total)
            break
    else:
        print('Four attempts failed.\nTry again later.')
        exit()

def change_pin():
    attempt=0
    while attempt<=3:
        pin2=input('\nEnter new pin:')
        if pin2.isdigit()==True and len(pin2)==4 and pin2!=pin:
            attempt2=0
            while attempt2<=3:
                pin3=input('Confirm new pin:')
                if pin2==pin3:
                    print("You've successfully changed your pin!\nYour new pin is:",pin3)
                    break
                else:
                    print('Invalid pin.\nTry again.')
                    attempt2+=1
            else:
                    print('Four attempts failed.\nThis card has been blocked.')
                    exit()
        else:
            print('Invalid pin.\nEnsure that new pin is of four digits and not same as old pin.\nTry again.')
            attempt+=1
    else:
        print('Four attempts failed.\nTry again later.')
        exit()

def operations():
    print('\nSelect any of the options by inputting the appropriate number.')
    print('1.Get Account Statement','\n2.Withdrawal','\n3.Deposit','\n4.Change Pin','\n5.Quit.')
    reply=input('Enter number:')
    if reply=='1':
        get_acct_statement()
    elif reply=='2':
        withdrawal()
    elif reply=='3':
        deposit()
    elif reply=='4':
        change_pin()
    elif reply=='5':
        exit()
    else:
        print('Invalid Input.\nThank you, for using Py Bank!')
        exit()

while True:
    operations()
    reply=input("\nWould you like to perfom another transaction?\nY or N:").lower()
    if reply=='y':
        continue
    elif reply=='n':
        print('Thank you, for using Py Bank!')
        break
    else:
        print('I do not understand.')
        exit()