diff --git a/tableauserverclient/server/endpoint/workbooks_endpoint.py b/tableauserverclient/server/endpoint/workbooks_endpoint.py
index 85c0f62c..4acd8140 100644
--- a/tableauserverclient/server/endpoint/workbooks_endpoint.py
+++ b/tableauserverclient/server/endpoint/workbooks_endpoint.py
@@ -139,8 +139,8 @@ def refresh(self, workbook_item: Union[WorkbookItem, str], incremental: bool = F
 
         Returns
         -------
-        JobItem
-            The job item.
+        JobItem | None
+            The job item, or None if a refresh job is already queued for this workbook.
         """
         id_ = getattr(workbook_item, "id", workbook_item)
         url = f"{self.baseurl}/{id_}/refresh"