[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

mypyc/irbuild/for_helpers.py

@@ -11,7 +11,6 @@
 
 from mypy.nodes import (
     ARG_POS,
-    BytesExpr,
     CallExpr,
     DictionaryComprehension,
     Expression,
@@ -23,10 +22,8 @@
     RefExpr,
     SetExpr,
     StarExpr,
-    StrExpr,
     TupleExpr,
     TypeAlias,
-    Var,
 )
 from mypyc.ir.ops import (
     ERR_NEVER,