In [8]:

    

class Counter(object): 
    number = 0 
 
    def __init__(self): 
        type(self).number += 1 
 
    def __del__(self): 
        type(self).number -= 1

class Account(Counter): 
    def __init__(self, 
                 account_holder,
                 account_number, 
                 balance, 
                 account_current=1500): 
        Counter.__init__(self)
        self.account_holder = account_holder
        self.account_number = account_number
        self.balance = balance
        self.account_current=account_current


    

In [13]:

    

c = Counter()
# class variable
Counter.number


    

    
Out[13]:





1

In [14]:

    

a = Account("Tom", 3384, 1000)
Account.number


    

    
Out[14]:





2

In [15]:

    

# instance variable
a.balance
a.account_current


    

    
Out[15]:





1000