Correct, this isn't intended to be an all-singing, all-dancing proxy
implementation - it's meant to be a simple solution for local proxies
that want to change the behaviour of a few operations while leaving
other operations unaffected.
The proposed documentation I uploaded covers some of its limitations.
However, even for those cases, ProxyMixin and/or
test_typetools.TestProxyMixin can be used as a reference to make sure a
custom proxy implementation correctly handles all the special method
invocations that can bypass __getattribute__.