''' create a bank account '''

class Bank:
    ''' create a bank account '''
    
    def __init__(self, amount):
        ''' initialize the initial amount'''
        self.balance = amount
    
    def deposit(self, amount):
        ''' deposit the amount into the balance'''
        self.balance = self.balance + amount
        
    def checkbalance(self):
        ''' return the current balance '''
        return self.balance
            
class Interest(Bank):
    ''' add some interest into your bank account'''
    
    def deposit(self, amount):
        Bank.deposit(self, amount)
        self.balance = self.balance * 1.05