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

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

Author: pre-commit-ci[bot]

pandas/tests/indexes/interval/test_setops.py

@@ -55,7 +55,7 @@ def test_union_empty_result(self, closed, sort):
         tm.assert_index_equal(result, expected)
 
         other = empty_index(dtype="uint64", closed=closed)
-        expected = Index([], dtype='object')
+        expected = Index([], dtype="object")
         result = index.union(other, sort=sort)
         tm.assert_index_equal(result, expected)
 
@@ -118,7 +118,7 @@ def test_intersection_empty_result(self, closed, sort):
         tm.assert_index_equal(result, expected)
 
         other = monotonic_index(300, 314, dtype="uint64", closed=closed)
-        expected = Index([], dtype='object')
+        expected = Index([], dtype="object")
         result = index.intersection(other, sort=sort)
         tm.assert_index_equal(result, expected)