class TransactionException(Exception):

    def __init__(self, *args, **kwargs):
        raise NotImplementedError('you should not be raising this')


class EverythingLostException(TransactionException):

    def __init__(self, msg):
        super(TransactionException, self).__init__(msg)
try:
    raise EverythingLostException('we are doomed!')
except TransactionException:
    pass
Можно ли объявить абстрактное исключение в Python?