Migrates models:note to Python 3
Migrates models:note to Python 3

PiperOrigin-RevId: 245987302
Change-Id: I0c8f40fa38f0486deb08ec2b623de4b38a14c9ad

google/upvote_py2,google/upvote_py2,google/upvote_py2,google/upvote_py2