some docstrings missing w/o 3.5

[jwkvam]

http://stackoverflow.com/questions/36143501/how-to-use-python-3-5-syntax-in-readthedocs-combined-with-autodoc/36144269#36144269

edit: scratch that I'll just wait for this to be resolved readthedocs/readthedocs.org#1990
until then the docstrings for the on_* methods won't show up, annoying but not a huge loss.

[jwkvam]

this is as good as it's gonna get