commit 5affd23e6f42125998724787025080a24839266e
author Serhiy Storchaka <storchaka@gmail.com> Wed Apr 05 09:37:24 2017 +0300
committer GitHub <noreply@github.com> Wed Apr 05 09:37:24 2017 +0300
tree 8b7ca82362e78a32805b117d574082d512251d3c
parent 43ba8861e0ad044efafa46a7cc04e12ac5df640e

bpo-29762: More use "raise from None". (#569)

This hides unwanted implementation details from tracebacks.

Lib/_weakrefset.py

diff --git a/Lib/_weakrefset.py b/Lib/_weakrefset.py
index 7f9923c..4d0de8c 100644
--- a/Lib/_weakrefset.py
+++ b/Lib/_weakrefset.py
@@ -98,7 +98,7 @@
             try:
                 itemref = self.data.pop()
             except KeyError:
-                raise KeyError('pop from empty WeakSet')
+                raise KeyError('pop from empty WeakSet') from None
             item = itemref()
             if item is not None:
                 return item