diff --git a/src/coroutine.rs b/src/coroutine.rs
index a530184a1c3..564262f3bf4 100644
--- a/src/coroutine.rs
+++ b/src/coroutine.rs
@@ -100,7 +100,7 @@ impl Coroutine {
         }
         // if waker has been waken during future polling, this is roughly equivalent to
         // `await asyncio.sleep(0)`, so just yield `None`.
-        Ok(IterNextOutput::Yield(py.None()))
+        Ok(IterNextOutput::Yield(py.None().into()))
     }
 }