enable torch.optim.swa_utils.SWALR (#42574)

Summary:
Fixes https://github.com/pytorch/pytorch/issues/42435

Pull Request resolved: https://github.com/pytorch/pytorch/pull/42574

Reviewed By: zou3519

Differential Revision: D22949369

Pulled By: vincentqb

fbshipit-source-id: f2f319ec94a97e0afe4d4327c866504ae632a986
diff --git a/torch/optim/__init__.py b/torch/optim/__init__.py
index 20fb940..5d36510 100644
--- a/torch/optim/__init__.py
+++ b/torch/optim/__init__.py
@@ -18,6 +18,7 @@
 from .optimizer import Optimizer
 from .lbfgs import LBFGS
 from . import lr_scheduler
+from . import swa_utils
 
 del adadelta
 del adagrad
diff --git a/torch/optim/__init__.pyi b/torch/optim/__init__.pyi
index d559204..f1ea0d3 100644
--- a/torch/optim/__init__.pyi
+++ b/torch/optim/__init__.pyi
@@ -1,3 +1,4 @@
+from . import swa_utils as swa_utils
 from . import lr_scheduler as lr_scheduler
 from .adadelta import Adadelta as Adadelta
 from .adagrad import Adagrad as Adagrad