inheritance.py

class A(Object):
    def a(self):
        logging.error('Fatal error!')
        sys.exit(1)

class B(A):
    def a(self):
        call_specific_dialog()
        super(B, self).a()
    
if __name__ == '__main__':
    test = B()
    test.a()

IMHO:

class A(object):
    def run(self):
        self.call_specific_dialog()
        logging.error('Fatal error!')
        sys.exit(1)

class B(A):
    def call_specific_dialog(self):
        self.do_b()

class C(A):
    def call_specific_dialog(self):
        self.do_c()