diff --git a/src/if_py_both.h b/src/if_py_both.h
index 1ad7dc6..e220e3f 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -5521,7 +5521,7 @@
     }
     else
     {
-	if (ConvertFromPyObject(run_ret, rettv) == -1)
+	if (run_ret != Py_None && ConvertFromPyObject(run_ret, rettv) == -1)
 	    EMSG(_("E859: Failed to convert returned python object to vim value"));
 	Py_DECREF(run_ret);
     }