diff --git a/qlib/finco/tpl/sl/workflow_config.yaml b/qlib/finco/tpl/sl/workflow_config.yaml
index 362725dc1..4c6c4821f 100644
--- a/qlib/finco/tpl/sl/workflow_config.yaml
+++ b/qlib/finco/tpl/sl/workflow_config.yaml
@@ -10,6 +10,7 @@ data_handler_config: &data_handler_config
     fit_start_time: 2008-01-01
     fit_end_time: 2014-12-31
     instruments: *market
+    label: "Ref($close, -21) / Ref($close, -1) - 1"
     infer_processors:
         - class: RobustZScoreNorm
           kwargs:
diff --git a/qlib/utils/mod.py b/qlib/utils/mod.py
index e53957260..22eddce8b 100644
--- a/qlib/utils/mod.py
+++ b/qlib/utils/mod.py
@@ -206,6 +206,9 @@ def find_all_classes(module_path: Union[str, ModuleType], cls: type) -> List[typ
         >>> from qlib.data.dataset.handler import DataHandler
         >>> find_all_classes("qlib.contrib.data.handler", DataHandler)
         [<class 'qlib.contrib.data.handler.Alpha158'>, <class 'qlib.contrib.data.handler.Alpha158vwap'>, <class 'qlib.contrib.data.handler.Alpha360'>, <class 'qlib.contrib.data.handler.Alpha360vwap'>, <class 'qlib.data.dataset.handler.DataHandlerLP'>]
+        >>> from qlib.contrib.rolling.base import Rolling
+        >>> find_all_classes("qlib.contrib.rolling", Rolling)
+        [<class 'qlib.contrib.rolling.base.Rolling'>, <class 'qlib.contrib.rolling.ddgda.DDGDA'>]
 
     TODO:
     - skip import error
@@ -220,7 +223,7 @@ def find_all_classes(module_path: Union[str, ModuleType], cls: type) -> List[typ
 
     def _append_cls(obj):
         # Leverage the closure trick to reuse code
-        if isinstance(obj, type) and issubclass(obj, cls) and cls not in cls_list:
+        if isinstance(obj, type) and issubclass(obj, cls) and obj not in cls_list:
             cls_list.append(obj)
 
     for attr in dir(mod):