Calling ConfigureWindow yields BadValue Errors as the code generation wrongly places the padding bytes after the value_list.
Switching the following lines in xproto.py fixes the error:
refer also to:
it was apparently introduced by 57934caa3fb207320c33312646d8e98290950f51
Fixed in xcb/proto master as of now.
Either recompile xpyb using xcb/proto from git, or wait until I do a release (should be soon).