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

pre-commit-ci[bot] · pre-commit-ci[bot] · commit 2188a17b88ee · 2023-04-03T19:54:57.000Z
for more information, see https://pre-commit.ci
diff --git a/xarray/core/groupby.py b/xarray/core/groupby.py
@@ -11,10 +11,7 @@
     Callable,
     Generic,
     Literal,
-    overload,
-    TypeVar,
     Union,
-    cast,
 )
 
 import numpy as np
