diff --git a/Lib/os.py b/Lib/os.py
index 2f78d8d..55e7fc2 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -446,7 +446,7 @@
         return len(self.data)
 
     def __repr__(self):
-        return 'environ({})'.format(', '.join(
+        return 'environ({{{}}})'.format(', '.join(
             ('{!r}: {!r}'.format(self.decodekey(key), self.decodevalue(value))
             for key, value in self.data.items())))