1 files changed, 2 insertions, 2 deletions
diff --git a/Lib/os.py b/Lib/os.py
index 06616c64d8..87689cc269 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -673,7 +673,7 @@ class _Environ(MutableMapping):
             value = self._data[self.encodekey(key)]
         except KeyError:
             # raise KeyError with the original key value
-            raise KeyError(key)
+            raise KeyError(key) from None
         return self.decodevalue(value)
 
     def __setitem__(self, key, value):
@@ -689,7 +689,7 @@ class _Environ(MutableMapping):
             del self._data[encodedkey]
         except KeyError:
             # raise KeyError with the original key value
-            raise KeyError(key)
+            raise KeyError(key) from None
 
     def __iter__(self):
         for key in self._data: