Optimize dict.fromkeys() with dict inputs. Useful for resetting bag/muliset counts for example.
diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index 7f0aabb..9f049ad 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -243,6 +243,10 @@
self.assertRaises(Exc, baddict2.fromkeys, [1])
+ # test fast path for dictionary inputs
+ d = dict(zip(range(6), range(6)))
+ self.assertEqual(dict.fromkeys(d, 0), dict(zip(range(6), [0]*6)))
+
def test_copy(self):
d = {1:1, 2:2, 3:3}
self.assertEqual(d.copy(), {1:1, 2:2, 3:3})