Hmm.. I know this is a python question, but DejaNews nor the Python website give me the answers I am looking for: I define a baseclass derived from CatalogAware and DTMLMethod: class Base(CatalogAware, DTMLMethod): def index_object(self): # check a few things I want to know about # before indexing, maybe even not allowing # the indexing CatalogAware.index_object(self) Then I define a bunch of classes based on this base class: class A(Base): pass class B(Base): pass etc. Now, if I do the following: a=A() a.index_object() I get a TypeError: unbound method must be called with class instance 1st argument Now, I have seen all sorts of messages relating this error, but none of them seem to relate to my problem... self in Vase.index_object _is_ a class instance, a step-by-step debug proves this. The python interpreter just won't accept it =(. -- Martijn Pieters, Web Developer | Antraciet http://www.antraciet.nl | Tel: +31-35-7502100 Fax: +31-35-7502111 | mailto:mj@antraciet.nl http://www.antraciet.nl/~mj | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 ------------------------------------------