diff --git a/src/freebox_api/access.py b/src/freebox_api/access.py
index f75c4363..0f230b15 100644
--- a/src/freebox_api/access.py
+++ b/src/freebox_api/access.py
@@ -143,6 +143,7 @@ async def post(
         """
         Send post request and return results
         """
+        data: Optional[str|Any] = None
         if json_transform:
             data = json.dumps(payload) if payload else None
         else: