A discussion on the python-ideas mailing list touched on a number of
interesting topics, from the problems with misspelled attribute names
through the design of security-sensitive interfaces and to the use of the
__slots__ attribute of objects. The latter may not be all that
well-known (or well-documented), but could potentially fix the problem at
hand, though not in a backward-compatible way. The conversation revolves
around the ssl module
in the standard library, which has been targeted for
upgrades, more than once,
over the years—with luck, the maintainers may find time for some upgrades relatively soon.

Source: LWN.net – [$] Python attributes, __slots__, and API design