Revert "Merge pull request #18859 from grpc/internal_py_proto_library"

.gitignore

WORKSPACE

bazel/generate_cc.bzl

bazel/grpc_python_deps.bzl

bazel/protobuf.bzl

bazel/python_rules.bzl

examples/BUILD

examples/python/errors/client.py

examples/python/errors/server.py

examples/python/errors/test/_error_handling_example_test.py

examples/python/multiprocessing/BUILD

examples/python/wait_for_ready/wait_for_ready_example.py

src/proto/grpc/channelz/BUILD

src/proto/grpc/health/v1/BUILD

src/proto/grpc/reflection/v1alpha/BUILD

src/proto/grpc/testing/BUILD

src/proto/grpc/testing/proto2/BUILD.bazel

src/python/grpcio_channelz/grpc_channelz/v1/BUILD.bazel

src/python/grpcio_health_checking/grpc_health/v1/BUILD.bazel

...hon/grpcio_reflection/grpc_reflection/v1alpha/BUILD.bazel