fix another possible race related to WeakValueDict

rpyc/lib/colls.py

@@ -37,6 +37,7 @@ def __getitem__(self, key):
         obj = self._dict[key]()
         if obj is None:
             raise KeyError(key)
+        self[key] = obj
         return obj
 
     def __setitem__(self, key, value):