[Zope] building product from the doc

[Aurélien Campéas]

Hello happy Zopers,

I'm currently trying to build a small & simple product, following
(closely) advice from
http://www.zope.org/Documentation/Books/ZDG/current/Products.stx

The doc is clear and well done, but now I'm stuck on this : when I try
to add some 'Candidat' (the meta_type of the product), I get from the
ZMI a 

Zope Error


Zope has encountered an error while publishing this resource.


Error Type: TypeError
 Error Value: addForm() takes no arguments (1 given)

etc...

In the doc example, addForm is really defined with no argument, and I
still don't see what knid of arg that ought to be.
I'm still investigating. Grepping around current existing products
doesn't help much since no installed product shows this very pattern (of
an addForm function defined as in the zope doc).

Thanks for your patience,

Aurélien.