When trying to build fedoraproject.org in my local copy:

Traceback (most recent call last):
  File "build/build.py", line 116, in <module>
    main()
  File "build/build.py", line 113, in main
    process(args)
  File "build/build.py", line 35, in process
    process_dir(dirpath, filenames)
  File "build/build.py", line 66, in process_dir
    ).render(method='html', doctype='html')
  File "/usr/lib64/python2.7/site-packages/genshi/core.py", line 183, in render
    return encode(generator, method=method, encoding=encoding, out=out)
  File "/usr/lib64/python2.7/site-packages/genshi/output.py", line 57, in encode
    return _encode(''.join(list(iterator)))
  File "/usr/lib64/python2.7/site-packages/genshi/output.py", line 470, in __call__
    for kind, data, _ in stream:
  File "/usr/lib64/python2.7/site-packages/genshi/output.py", line 826, in __call__
    for kind, data, pos in stream:
  File "/usr/lib64/python2.7/site-packages/genshi/output.py", line 670, in __call__
    for kind, data, pos in stream:
  File "/usr/lib64/python2.7/site-packages/genshi/output.py", line 771, in __call__
    for kind, data, pos in chain(stream, [(None, None, None)]):
  File "/usr/lib64/python2.7/site-packages/genshi/output.py", line 586, in __call__
    for ev in stream:
  File "/usr/lib64/python2.7/site-packages/genshi/core.py", line 272, in _ensure
    event = stream.next()
  File "/usr/lib64/python2.7/site-packages/genshi/template/base.py", line 605, in _include
    for event in stream:
  File "/usr/lib64/python2.7/site-packages/genshi/template/markup.py", line 327, in _match
    for event in stream:
  File "/usr/lib64/python2.7/site-packages/genshi/template/base.py", line 545, in _flatten
    for kind, data, pos in stream:
  File "/usr/lib64/python2.7/site-packages/genshi/filters/i18n.py", line 666, in __call__
    gettext = self.translate.ugettext
AttributeError: 'function' object has no attribute 'ugettext'

See also: http://bugs.python.org/issue8508