I found one problem with pop-diff

[vekergu]

the code:
def diff(r1, r2, include_fresh=False, include_stale=False, excludes=None):
include_versions = True if include_stale else False
excludes = excludes if len(excludes) else []

in python 2.7.1.4
if excludes=None
then len(excludes) is error