matplotlib/matplotlib — pull request #2909 by tacaswell (2014-03-19 16:56:29+00:00)
Title: BUG : add __hash__ to AffineBase

python3 requires that if a class defines __eq__ then in must define
__hash__ (so that if a == b then hash(a) == hash(b)). Define 64bit
hash by pulling the first 8 characters out of a sha1 hash of the matrix

closes #2828