Add missing typevar to python utils

python/util.py

@@ -5,7 +5,7 @@
 import numbers
 import os
 from collections import defaultdict
-from typing import List, Tuple, Dict, Set
+from typing import List, Tuple, Dict, Set, TypeVar
 
 
 def build_graph(max_cols, max_rows, target_model):
@@ -507,6 +507,9 @@ def _to_js(sizes_strides):
     """
 
 
+E = TypeVar("E")
+
+
 def single_elem_or_list_to_list(val: list[E] | E) -> list[T]:
     """does not work for list of lists but still useful"""
     if not isinstance(val, list):