Update tableauserverclient/server/endpoint/workbooks_endpoint.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: jacalata

tableauserverclient/server/endpoint/workbooks_endpoint.py

@@ -149,7 +149,7 @@ def refresh(self, workbook_item: Union[WorkbookItem, str], incremental: bool = F
         try:
             server_response = self.post_request(url, refresh_req)
         except ServerResponseError as e:
-            if e.code.startswith("409") and e.detail.find("already"):
+            if e.code.startswith("409") and "already" in e.detail:
                 print(e.summary + " " + e.detail)
                 return None
             else: