[caffe2] Explicitly define all DataTypes in python/core.py (#51768)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51768
This updates python/core.py to explicitly define all of the `DataType`
values rather than dynamically defining them at runtime from the
`caffe2_pb2` values.
This allows type checkers like Pyre and Mypy to see the members of the
`DataType` class. Otherwise the type checkers report errors such as
`"core.DataType" has no attribute "INT64"`.
This code does keep a run-time check that all of the data types defined
by `caffe2_pb2.proto` are defined correctly in this file. This way if
someone does add a new type to `caffe2_pb2.proto` it should be very
quickly apparent that this file needs to be updated and kept in sync.
ghstack-source-id: 121936201
Test Plan:
Confirmed that various caffe2/python tests still pass.
Verified that this allows many `pyre-fixme` comments to be removed in
downstream projects, and that Pyre is still clean for these projects.
Reviewed By: jeffdunn
Differential Revision: D26271725
Pulled By: simpkins
fbshipit-source-id: f9e95795de60aba67d7d3872d0c141ed82ba8e39
