fix some small bug

qlib/utils/__init__.py

@@ -185,7 +185,7 @@ def get_cls_kwargs(config: Union[dict, str], module) -> (type, dict):
     if isinstance(config, dict):
         # raise AttributeError
         klass = getattr(module, config["class"])
-        kwargs = config["kwargs"]
+        kwargs = config.get("kwargs", {})
     elif isinstance(config, str):
         klass = getattr(module, config)
         kwargs = {}
@@ -619,6 +619,28 @@ def exists_qlib_data(qlib_dir):
     return True
 
 
+def lexsort_index(df: pd.DataFrame) -> pd.DataFrame:
+    """
+    make the df index lexsorted
+
+    df.sort_index() will take a lot of time even when `df.is_lexsorted() == True`
+    This function could avoid such case
+
+    Parameters
+    ----------
+    df : pd.DataFrame
+
+    Returns
+    -------
+    pd.DataFrame:
+        sorted dataframe
+    """
+    if df.index.is_lexsorted():
+        return df
+    else:
+        return df.sort_index()
+
+
 #################### Wrapper #####################
 class Wrapper(object):
     """Data Provider Wrapper"""