I'm getting this error when I try to commit to repohooks:

Traceback (most recent call last):
  File "./pre-upload_unittest.py", line 24, in <module>
    from chromite.lib import cros_test_lib
  File "/usr/local/google/home/ljusten/chromiumos/src/repohooks/../../chromite/lib/cros_test_lib.py", line 19, in <module>
    import mox
ImportError: No module named mox

This is run from repohooks/PRESUBMIT.cfg.