# OOP
class Account(object):
    """A bank account that allows deposits and withdrawals.

    >>> john = Account('John')
    >>> jack = Account('Jack')
    >>> john.deposit(10)
    10
    >>> john.deposit(5)
    15
    >>> john.interest
    0.02
    >>> jack.deposit(7)
    7
    >>> jack.deposit(5)
    12
    """

    interest = 0.02

    def __init__(self, account_holder):
        self.balance = 0
        self.holder = account_holder

    def deposit(self, amount):
        """Increase the account balance by amount and return the new balance."""
        self.balance = self.balance + amount
        return self.balance

    def withdraw(self, amount):
        """Decrease the account balance by amount and return the new balance."""
        if amount > self.balance:
            return 'Insufficient funds'
        self.balance = self.balance - amount
        return self.balance

# Currying to get a bound method
from operator import add

def curry(f):
    def outer(x):
        def inner(*args):
            return f(x, *args)
        return inner
    return outer

add3 = curry(add)(3)
add3(4)

tom_account = Account('Tom')
tom_deposit = curry(Account.deposit)(tom_account)
tom_deposit(1000)

# Inheritance
class CheckingAccount(Account):
    """A bank account that charges for withdrawals.

    >>> ch = CheckingAccount('Jack')
    >>> ch.balance = 20
    >>> ch.withdraw(5)
    14
    >>> ch.interest
    0.01
    """

    withdraw_fee = 1
    interest = 0.01

    def withdraw(self, amount):
        fee = self.withdraw_fee
        return Account.withdraw(self, amount+fee)

class SavingsAccount(Account):
    """A bank account that charges for deposits."""

    deposit_fee = 2

    def deposit(self, amount):
        return Account.deposit(self, amount - self.deposit_fee)

class AsSeenOnTVAccount(CheckingAccount, SavingsAccount):
    """A bank account that charges for everything."""

    def __init__(self, account_holder):
        self.holder = account_holder
        self.balance = 1           # A free dollar!

supers = [c.__name__ for c in AsSeenOnTVAccount.mro()]