rename fix

dios/base.py

@@ -327,6 +327,9 @@ class _DiosBase:
         if not index.is_unique:
             raise ValueError("columns index must have unique values")
         self._data.index = index
+        # rename all columns
+        for i, s in enumerate(self._data):
+            s.name = index[i]
 
     @property
     def itype(self):