Adding new built-in function sum, with docs and tests.
diff --git a/Misc/NEWS b/Misc/NEWS
index 2897793..330831d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@
Core and builtins
-----------------
+- New builtin function sum(seq, start=0) returns the sum of all the
+ items in iterable object seq, plus start (items are normally numbers,
+ and cannot be strings).
+
- bool() called without arguments now returns False rather than
raising an exception. This is consistent with calling the
constructors for the other builtin types -- called without argument