Bug #1675967: re patterns pickled with older Python versions can
now be unpickled.
 (backport form rev. 54492)
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index 14a0acf..a885180 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -414,6 +414,15 @@
         self.pickle_test(pickle)
         import cPickle
         self.pickle_test(cPickle)
+        # old pickles expect the _compile() reconstructor in sre module
+        import warnings
+        original_filters = warnings.filters[:]
+        try:
+            warnings.filterwarnings("ignore", "The sre module is deprecated",
+                                    DeprecationWarning)
+            from sre import _compile
+        finally:
+            warnings.filters = original_filters
 
     def pickle_test(self, pickle):
         oldpat = re.compile('a(?:b|(c|e){1,2}?|d)+?(.)')