From 379bf9d072ec3e9244e0b8c7555931dcf5406810 Mon Sep 17 00:00:00 2001
From: Richard Kleijn <rkleijn@gmail.com>
Date: Sun, 3 Jul 2022 10:47:10 +0200
Subject: [PATCH] fix some mypy errors

---
 xarray/core/rolling.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/xarray/core/rolling.py b/xarray/core/rolling.py
index 916fabe42ac..55901d56424 100644
--- a/xarray/core/rolling.py
+++ b/xarray/core/rolling.py
@@ -4,7 +4,7 @@
 import itertools
 import math
 import warnings
-from collections.abc import Hashable, Iterator, Mapping
+from collections.abc import Hashable, Iterator, Mapping, Sequence
 from typing import TYPE_CHECKING, Any, Callable, Generic, TypeVar
 
 import numpy as np
@@ -467,9 +467,8 @@ def reduce(
             obj, rolling_dim, keep_attrs=keep_attrs, fill_value=fillna
         )
 
-        result = windows.reduce(
-            func, dim=list(rolling_dim.values()), keep_attrs=keep_attrs, **kwargs
-        )
+        dim: Sequence[Hashable] = list(rolling_dim.values())
+        result = windows.reduce(func, dim=dim, keep_attrs=keep_attrs, **kwargs)
 
         # Find valid windows based on count.
         counts = self._counts(keep_attrs=False)
@@ -486,6 +485,7 @@ def _counts(self, keep_attrs: bool | None) -> DataArray:
         # array is faster to be reduced than object array.
         # The use of skipna==False is also faster since it does not need to
         # copy the strided array.
+        dim: Sequence[Hashable] = list(rolling_dim.values())
         counts = (
             self.obj.notnull(keep_attrs=keep_attrs)
             .rolling(
@@ -493,7 +493,7 @@ def _counts(self, keep_attrs: bool | None) -> DataArray:
                 center={d: self.center[i] for i, d in enumerate(self.dim)},
             )
             .construct(rolling_dim, fill_value=False, keep_attrs=keep_attrs)
-            .sum(dim=list(rolling_dim.values()), skipna=False, keep_attrs=keep_attrs)
+            .sum(dim=dim, skipna=False, keep_attrs=keep_attrs)
         )
         return counts