Expose importlib.util.set___package__.
diff --git a/Lib/importlib/util.py b/Lib/importlib/util.py
index 6250d5b..2b6154b 100644
--- a/Lib/importlib/util.py
+++ b/Lib/importlib/util.py
@@ -1,2 +1,3 @@
 """Utility code for constructing importers, etc."""
 from ._bootstrap import module_for_loader
+from ._bootstrap import set___package__