bpo-36326: Let inspect.getdoc() find docstrings for __slots__ (GH-12498)


diff --git a/Lib/test/test_statistics.py b/Lib/test/test_statistics.py
index 485ffe2..7f7839d 100644
--- a/Lib/test/test_statistics.py
+++ b/Lib/test/test_statistics.py
@@ -2051,7 +2051,7 @@
         nd = statistics.NormalDist(300, 23)
         with self.assertRaises(TypeError):
             vars(nd)
-        self.assertEqual(nd.__slots__, ('mu', 'sigma'))
+        self.assertEqual(tuple(nd.__slots__), ('mu', 'sigma'))
 
     def test_instantiation_and_attributes(self):
         nd = statistics.NormalDist(500, 17)