Inyeol Lee wrote: (snip) >>>>class A(object): >>>>... def __init__(self, foo): >>>>... if self.__class__ is A: >>>>... raise TypeError("A is base class.") s/TypeError/NotImplementedError/ s/base class/abstract class/ -- bruno desthuilliers python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for p in 'onurb at xiludom.gro'.split('@')])"