Update for_helpers.py

Author: BobTheBuidler

mypyc/irbuild/for_helpers.py

@@ -7,7 +7,7 @@
 
 from __future__ import annotations
 
-from typing import Callable, ClassVar, Optional,
+from typing import Callable, ClassVar, Optional
 
 from mypy.nodes import (
     ARG_POS,