Move istype and object identity tests into a dispatching dictionary. (#95476)
The idea is to make it a little more obvious which branch you're going to go down in a subset of cases, and make it easier to detect if you've accidentally shadowed one condition with another (the reason I wrote this in the first place.) The type dictionary also makes it harder for people to accidentally use isinstance when they should have used istype.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/95476
Approved by: https://github.com/jansel
