1 files changed, 2 insertions, 2 deletions
diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py
index 005d884..e89e84b 100644
--- a/Lib/_collections_abc.py
+++ b/Lib/_collections_abc.py
@@ -589,7 +589,7 @@ class MutableSet(Set):
         try:
             value = next(it)
         except StopIteration:
-            raise KeyError
+            raise KeyError from None
         self.discard(value)
         return value
 
@@ -808,7 +808,7 @@ class MutableMapping(Mapping):
         try:
             key = next(iter(self))
         except StopIteration:
-            raise KeyError
+            raise KeyError from None
         value = self[key]
         del self[key]
         return key, value