Issue #18076: Introduce imoportlib.util.decode_source().
The helper function makes it easier to implement
imoprtlib.abc.InspectLoader.get_source() by making that function
require just the raw bytes for source code and handling all other
details.
diff --git a/Lib/importlib/util.py b/Lib/importlib/util.py
index 06f4d2f..7727f9d 100644
--- a/Lib/importlib/util.py
+++ b/Lib/importlib/util.py
@@ -2,6 +2,7 @@
from ._bootstrap import MAGIC_NUMBER
from ._bootstrap import cache_from_source
+from ._bootstrap import decode_source
from ._bootstrap import module_to_load
from ._bootstrap import set_loader
from ._bootstrap import set_package