Issue #18189: add test_delegator for Idle Delegator class.

Also change private dict used as a set to a set.

1 files changed, 2 insertions, 2 deletions

diff --git a/Lib/idlelib/Delegator.py b/Lib/idlelib/Delegator.py
index 362c7cdfe2..c4765163f8 100644
--- a/Lib/idlelib/Delegator.py
+++ b/Lib/idlelib/Delegator.py
@@ -4,12 +4,12 @@ class Delegator:
 
     def __init__(self, delegate=None):
         self.delegate = delegate
-        self.__cache = {}
+        self.__cache = set()
 
     def __getattr__(self, name):
         attr = getattr(self.delegate, name) # May raise AttributeError
         setattr(self, name, attr)
-        self.__cache[name] = attr
+        self.__cache.add(name)
         return attr
 
     def resetcache(self):