diff --git a/qlib/data/storage/storage.py b/qlib/data/storage/storage.py
index 8207b5c9aa..5d1d2f06b7 100644
--- a/qlib/data/storage/storage.py
+++ b/qlib/data/storage/storage.py
@@ -124,12 +124,12 @@ def remove(self, value: CalVT) -> None:
 
     @overload
     def __setitem__(self, i: int, value: CalVT) -> None:
-        """x.__setitem__(i, o) <==> x[i] = o"""
+        """x.__setitem__(i, o) <==> (x[i] = o)"""
         ...
 
     @overload
     def __setitem__(self, s: slice, value: Iterable[CalVT]) -> None:
-        """x.__setitem__(s, o) <==> x[s] = o"""
+        """x.__setitem__(s, o) <==> (x[s] = o)"""
         ...
 
     def __setitem__(self, i, value) -> None:
@@ -364,7 +364,12 @@ def rewrite(self, data: Union[List, np.ndarray, Tuple], index: int):
 
     @overload
     def __getitem__(self, s: slice) -> pd.Series:
-        """x.__getitem__(slice(start: int, stop: int, step: int)) <==> x[start:stop:step] == pd.Series(values, index=pd.RangeIndex(start, len(values))"""
+        """x.__getitem__(slice(start: int, stop: int, step: int)) <==> x[start:stop:step]
+
+        Returns
+        -------
+            pd.Series(values, index=pd.RangeIndex(start, len(values))
+        """
         ...
 
     @overload