update rolling process

examples/rolling_process_data/rolling_handler.py

@@ -0,0 +1,34 @@
+from qlib.data.dataset.handler import DataHandlerLP
+from qlib.data.dataset.loader import DataLoaderDH
+from qlib.contrib.data.handler import check_transform_proc
+
+
+class RollingDataHandler(DataHandlerLP):
+    def __init__(
+        self,
+        start_time=None,
+        end_time=None,
+        infer_processors=[],
+        learn_processors=[],
+        fit_start_time=None,
+        fit_end_time=None,
+        data_loader_kwargs={}
+    ):
+        infer_processors = check_transform_proc(infer_processors, fit_start_time, fit_end_time)
+        learn_processors = check_transform_proc(learn_processors, fit_start_time, fit_end_time)
+
+        data_loader = {
+            "class": "DataLoaderDH",
+            "kwargs": {
+                **data_loader_kwargs
+            },
+        } 
+
+        super().__init__(
+            instruments=None,
+            start_time=start_time,
+            end_time=end_time,
+            data_loader=data_loader,
+            infer_processors=infer_processors,
+            learn_processors=learn_processors,
+        )