diff --git a/pyobs/robotic/scripts/callmodule.py b/pyobs/robotic/scripts/callmodule.py
index d59c1838..54884be8 100644
--- a/pyobs/robotic/scripts/callmodule.py
+++ b/pyobs/robotic/scripts/callmodule.py
@@ -18,7 +18,7 @@ def __init__(
         self,
         module: str,
         method: str,
-        params: Optional[List[Any]],
+        params: Optional[List[Any]] = None,
         **kwargs: Any,
     ):
         """Initialize a new SequentialRunner.