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

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datatree/tests/test_mapping.py

@@ -252,7 +252,9 @@ def times_ten(ds):
         result_tree = times_ten(subtree)
         assert_equal(result_tree, expected, from_root=False)
 
-    @pytest.mark.xfail(reason='probably some bug in pytests handling of exception notes')
+    @pytest.mark.xfail(
+        reason="probably some bug in pytests handling of exception notes"
+    )
     def test_error_contains_path_of_offending_node(self, create_test_datatree):
         dt = create_test_datatree()
         dt["set1"]["bad_var"] = 0