diff --git a/clvm/SExp.py b/clvm/SExp.py
index 0f22a99f..48e90316 100644
--- a/clvm/SExp.py
+++ b/clvm/SExp.py
@@ -217,7 +217,7 @@ def null(class_) -> SExp:
 
     def as_iter(self: _T_SExp) -> typing.Iterator[_T_SExp]:
         v = self
-        while not v.nullp():
+        while v.pair is not None:
             yield v.first()
             v = v.rest()
 
diff --git a/tests/as_python_test.py b/tests/as_python_test.py
index 5c5c0d3d..092e7bad 100644
--- a/tests/as_python_test.py
+++ b/tests/as_python_test.py
@@ -223,11 +223,12 @@ def test_as_iter(self) -> None:
         val = list(SExp.to((1, b"")).as_iter())
         self.assertEqual(val, [1])
 
-        # these fail because the lists are not null-terminated
-        self.assertRaises(EvalError, lambda: list(SExp.to(1).as_iter()))
-        self.assertRaises(
-            EvalError, lambda: list(SExp.to((1, (2, (3, (4, 5))))).as_iter())
-        )
+        # we accept lists that are not null-terminated
+        val = list(SExp.to(1).as_iter())
+        self.assertEqual(val, [])
+
+        val = list(SExp.to((1, (2, (3, (4, 5))))).as_iter())
+        self.assertEqual(val, [1, 2, 3, 4])
 
     def test_eq(self) -> None:
         val = SExp.to(1)