abc2.py

class Banking(object):
    """ Payment processor that does nothing, just logs """
    def __init__(self):
        self._logger = logging.getLogger(__name__)
        self._logger.setLevel(logging.INFO)
 
    def process_payment(self, destination_address, amount):
        """ Execute a payment to one receiving single address

        return the transaction id or None """
        raise NotImplementedError("Not implemented yet")
 
 
class BankingBank1(Banking):
    """docstring for BankingBank1"""
    def __init__(self, arg):
        super(BankingBank1, self).__init__()
        self.arg = arg
 
 
    def process_payment(self, destination_address, amount):
        """ Execute a payment to one receiving single address
 
        return the transaction id or None """
        print('process payment for bank 1')
 
 
class BankingBank2(Banking):
    """docstring for BankingBank1"""
    def __init__(self, arg):
        super(BankingBank2, self).__init__()
        self.arg = arg
 
 
def user_action(bb_obj):
    if isinstance(bb_obj, BankingBank1):
        bb_obj.process_payment('destination_address', 100)
    elif isinstance(bb_obj, BankingBank2):
        print('Cannot process the payment.')
    else:
        print('implement this.')
 
 
bb2 = BankingBank2(__name__)
user_action(bb2)