Help Me With My A-Level Python Banking System Project

[TickleMeElmo]

Hey guys,

I'm in desparate need of assistance with my A-Level project.
I'm writing a Banking system in Python and I'm being told by the idle log that a function hasn't been defined - even though that function is right above it!

My Full Code is:

    #'http://effbot.org/tkinterbook/tkinter-index.htm' <<< Tkinter Tutorials
    #Ignore the link above, it's for future reference

    import time
    import random

    class BankAccount():

      #Class Initialisation
        def __init__(self, firstName, lastName, accountNumber, pinNumber, balance=0):
            self.fn = firstName
            self.ln = lastName
            self.accNum = accountNumber
            self.pin = pinNumber
            self.bal = balance
            self.transactions = []

      #Class Functions
        def deposit(self, amount):
            self.bal += amount
            return self.bal

        def withdraw(self, amount):
            if self.bal - amount > 0:
                self.bal -= amount
                self.transactions.append(-amount)
                time.sleep(.25)
                print('\n[Your new balance is £{}]\n'.format(self.bal))
            else: 
                time.sleep(.25)
                print('\n[You must withdraw a number greater than zero]\n')

        def accinfo(self):
            print('\n')
            print('-'*50)
            print('                Account Information')
            print('-'*50)
            print('Account Holder: {} {}'.format(self.fn, self.ln))
            print('Account Balance: £{}'.format(self.bal))
            print('Account Number: {}'.format(self.accNum))
            print('Account Pin: {}\n'.format(self.pin))

      #Setters
        def setfn(self, firstName):
            self.fn = firstName
            print('\n[First Name Updated]\n')

        def setln(self, lastName):
            self.ln = lastName
            print('\n[Last Name Updated]\n')

        def setNewAccNum(self):
            self.accNum = random.randint(0000,9999)
            print('\n[Account Number: {}]\n'.format(self.accNum))

        def setNewPin(self):
            self.pin = random.randint(0000, 9999)
            print('\n[Pin Number: {}]\n'.format(self.pin))

        def login():
            time.sleep(.25)

            accNum = random.randint(0000, 9999)
            pinNum = random.randint(0000, 9999)
            bal = 1000

            firstName = input('Please enter your first name: ')
            lastName = input('Please enter your last name: ')
            password = input('Please enter your password: ')
            for line in open('credentials.txt','r').readlines():
                login_info = line.split()
                if firstName == login_info[0] and lastName == login_info[1] and password == login_info[2]:
                    acc = BankAccount(firstName, lastName, accNum, pinNum, bal)
                    print('Logging in...')
                    time.sleep(.25)
                    accinfo()
                else:
                    print('WRONG LOL GET LOST U NUB')
                    exit()

        def newAccount():
            time.sleep(.25)
            firstName = input('Please input your first name: ')
            lastName = input('Please input your last name: ')
            password = input('Please input a password: ')
            file = open('credentials.txt','a')
            file.write(firstName)
            file.write(' ')
            file.write(lastName)
            file.write(' ')
            file.write(password)
            file.write('\n')
            file.close()
            print('\nThe Bank has rewarded you with 1000 GBP for opening an account with us!\n')
            print('Account Opened! Now try logging on\n')
            mainloop()

        def mainloop():
            print('-'*50)
            print('              The Royal Mint Of Spain')
            print('-'*50+'\n')
            print('•  Enter Input [1-4]')
            print('1) Login')
            print('2) Open Account')
            print('3) Exit\n')
            choice = input('>>>')

            if choice == '1': login()
            elif choice == '2': newAccount()
            elif choice == '3': exit(time.sleep(.25))
            else:
                print('[Invalid Input]')
                mainloop()

        mainloop()

    test = BankAccount('Test','Testerson', 1234, 5678, 1000)

Idle is telling me the following:

Traceback (most recent call last):
  File "H:\My Documents\Computing\Python\Object Oriented Programming\Banking System\main.py", line 6, in <module>
    class BankAccount():
  File "H:\My Documents\Computing\Python\Object Oriented Programming\Banking System\main.py", line 114, in BankAccount
    mainloop()
  File "H:\My Documents\Computing\Python\Object Oriented Programming\Banking System\main.py", line 107, in mainloop
    if choice == '1': login()
NameError: global name 'login' is not defined

I would appreciate any help!

Thanks!

[Reverend Jim]

Start by taking mainloop out of the class. Make other methods (like login) actual class methods. Put your loop in the main line as

while True:
    print('-'*50)
    print('              The Royal Mint Of Spain')
    print('-'*50+'\n')
    print('  Enter Input [1-4]')
    print('1) Login')
    print('2) Open Account')
    print('3) Exit\n')
    choice = input('>>>')
    if choice   == '1': test.login()
    elif choice == '2': test.newAccount()
    elif choice == '3': sys.exit()
    else:
        print('[Invalid Input]')

[woooee]

login() is declared uner the class, even though it is not a member of the class.