diff --git a/lib/Crypto/SelfTest/Protocol/test_HPKE.py b/lib/Crypto/SelfTest/Protocol/test_HPKE.py
index ee6ae94a..18e5de17 100644
--- a/lib/Crypto/SelfTest/Protocol/test_HPKE.py
+++ b/lib/Crypto/SelfTest/Protocol/test_HPKE.py
@@ -51,7 +51,7 @@ def round_trip(self, curve, aead_id):
         self.assertEqual(b'GHI', pt2)
 
     def test_round_trip(self):
-        for curve in self.curves.keys():
+        for curve in self.curves:
             for aead_id in HPKE.AEAD:
                 self.round_trip(curve, aead_id)