diff --git a/server_environment/serv_config.py b/server_environment/serv_config.py
index 1645e70..9ce6429 100644
--- a/server_environment/serv_config.py
+++ b/server_environment/serv_config.py
@@ -108,7 +108,8 @@ class _Defaults(dict):
     __slots__ = ()
 
     def __setitem__(self, key, value):
-        func = lambda *a: str(value)
+        def func(*a):
+            return str(value)
         return dict.__setitem__(self, key, func)