diff --git a/qlib/utils/index_data.py b/qlib/utils/index_data.py
index ddc2694dfe..715040538a 100644
--- a/qlib/utils/index_data.py
+++ b/qlib/utils/index_data.py
@@ -141,7 +141,7 @@ def _convert_type(self, item):
             elif isinstance(item, np.datetime64):
                 # This happens often when creating index based on np.datetime64 and query with another precision
                 return item.astype(self.idx_list.dtype)
-            # NOTE: It is hard to consider every cases at first. 
+            # NOTE: It is hard to consider every case at first. 
             # We just try to cover part of cases to make it more user-friendly 
         return item