use assert[Not]In where appropriate
diff --git a/Lib/test/test_sets.py b/Lib/test/test_sets.py
index 9c59836..ca049a4 100644
--- a/Lib/test/test_sets.py
+++ b/Lib/test/test_sets.py
@@ -76,7 +76,7 @@
 
     def test_iteration(self):
         for v in self.set:
-            self.assertTrue(v in self.values)
+            self.assertIn(v, self.values)
 
     def test_pickling(self):
         p = pickle.dumps(self.set)
@@ -406,7 +406,7 @@
             popped[self.set.pop()] = None
         self.assertEqual(len(popped), len(self.values))
         for v in self.values:
-            self.assertTrue(v in popped)
+            self.assertIn(v, popped)
 
     def test_update_empty_tuple(self):
         self.set.union_update(())