diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -4885,6 +4885,24 @@
     def test_nargs_3_metavar_length3(self):
         self.do_test_no_exception(nargs=3, metavar=("1", "2", "3"))
 
+# ==========================
+# add_argument choices tests
+# ==========================
+
+class TestAddArgumentChoices(TestCase):
+
+    def test_non_iterable_choices(self):
+        """Check that adding a non-iterable choices argument raises TypeError.
+        This also checks that it is not sufficient to support just the "in"
+        operator (e.g. by implementing __contains__).  See issue #16468."""
+        class NonIterableChoices(object):
+            def __contains__(self, item):
+                return True
+        parser = argparse.ArgumentParser()
+        self.assertRaises(TypeError, parser.add_argument, "foo",
+                          choices=NonIterableChoices())
+
+
 # ============================
 # from argparse import * tests
 # ============================