These were removed by 88dbb31daa under the assumption that they were not used, but it has recently come to my attention that there is still code out there that uses these.
PriorityCallbacks has been updated to be compatible with Python 3 by only comparing the priority, rather than the (priority, callback) tuple. This also has the side-effect of ditching the bisect dependency.
Also moves testing code from the source to the unit tests.
WMOkiishi
rdb
pythonengineer