diff --git a/knockapi/resources/workflows.py b/knockapi/resources/workflows.py
index 81b113e..8ce7430 100644
--- a/knockapi/resources/workflows.py
+++ b/knockapi/resources/workflows.py
@@ -76,7 +76,7 @@ def create_schedules(
             self,
             key,
             recipients,
-            repeats=None,
+            repeats=[],
             scheduled_at=None,
             data={},
             actor=None,