str concatenation in the test broke mypy

Author: invalidarg

pandas/tests/io/formats/style/test_style.py

@@ -893,13 +893,10 @@ def test_maybe_convert_css_to_tuples(self):
         #if no value, return attr and empty string
         expected = [("a", ""), ("c", "")]
         assert maybe_convert_css_to_tuples("a:;c: ") == expected
-        
 
     def test_maybe_convert_css_to_tuples_err(self):
-        msg = (
-            "Styles supplied as string must follow CSS rule formats, "
-            "for example 'attr: val;'. 'err' was given."
-        )
+        msg = "Styles supplied as string must follow CSS rule formats, " \
+          "for example 'attr: val;'. 'err' was given."
         with pytest.raises(ValueError, match=msg):
             maybe_convert_css_to_tuples("err")