This is my nearly two year old patch
[ 400998 ] experimental support for extended slicing on lists
somewhat spruced up and better tested than it was when I wrote it.
Includes docs & tests. The whatsnew section needs expanding, and arrays
should support extended slices -- later.
diff --git a/Lib/test/test_bool.py b/Lib/test/test_bool.py
index 4a8bef1..cadf23a 100644
--- a/Lib/test/test_bool.py
+++ b/Lib/test/test_bool.py
@@ -219,7 +219,7 @@
veris(operator.isSequenceType([]), True)
veris(operator.contains([], 1), False)
veris(operator.contains([1], 1), True)
-veris(operator.isMappingType([]), False)
+veris(operator.isMappingType(1), False)
veris(operator.isMappingType({}), True)
veris(operator.lt(0, 0), False)
veris(operator.lt(0, 1), True)