sync.py broken in Python3

[april]

If I run sync.py with Python3, I get the following traceback:

$ ./sync.py -d
Traceback (most recent call last):
  File "sync.py", line 124, in <module>
    main(opts, args)
  File "sync.py", line 105, in main
    compare_site_and_disk(config, diff, site, docs, push, get)
  File "sync.py", line 47, in compare_site_and_disk
    m_ondisk.update(on_disk)
TypeError: Unicode-objects must be encoded before hashing