A clever union-find implementation from c.l.py, due to David Eppstein. This is another one that leaks memory without an explict clear!  Time to bite this bullet.
A clever union-find implementation from c.l.py, due to David Eppstein.
This is another one that leaks memory without an explict clear!  Time to
bite this bullet.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator