enthought/enaml — comment on commit 64e92258bb7a102dfc8a6f7fac4241a1e368b3f8
File: enaml/guard.py line 25
By rkern:

This is not a particularly good place to use `__slots__`. The general rule is that `__slots__` is only worthwhile when you have a million or so of the items in memory at a time. Obviously, there aren't going to be a million of these.