When inserting a class skeleton in python mode (C-c C-t c) and
entering an empty value at the inheritance prompt, the last character of
the class name is deleted.

To reproduce, start emacs with the -Q switch; Then press:

C-x h C-w M-x p y t h o n SPC m o d <tab> <return> 
C-c C-t c T e s t <return> <return> <menu> r e p o 
r <tab> <return>

Here is a patch to fix that problem: