Update custom_tools.py

custom_tools.py

@@ -432,7 +432,8 @@ class ExtractTableFromWebpageTool(Tool):
         },
         "table_identifier": {
             "type": "string",
-            "description": "The index (e.g., '0' for the first table, '1' for the second) or a text keyword from the table's caption to identify which table to extract. Defaults to '0'."
+            "description": "The index (e.g., '0' for the first table, '1' for the second) or a text keyword from the table's caption to identify which table to extract. Defaults to '0'.",
+            "nullable": True
         }
     }