I did it here: https://github.com/ContinuumIO/bokeh/pull/581/files#diff-1ffaba883bd32df7e41a116e47b7be1fR60
In fact, one of the things I am changing in the upcoming PR is merge pyplot.py into mpl.py... it makes no sense to have it separately, because pyplot is small now, and even really small in the new branch...