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

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

Author: pre-commit-ci[bot]

traitlets/tests/test_traitlets.py

@@ -3138,10 +3138,7 @@ def test_tcp_from_string(s, expected):
 
 @pytest.mark.parametrize(
     "s, expected",
-    [
-        ("[]", []),
-        ('{}', '{}')
-    ],
+    [("[]", []), ("{}", "{}")],
 )
 def test_union_of_list_and_unicode_from_string(s, expected):
     _from_string_test(Union([List(), Unicode()]), s, expected)

traitlets/traitlets.py

@@ -2189,7 +2189,6 @@ def from_string(self, s):
         self.error(None, s)
 
 
-
 # -----------------------------------------------------------------------------
 # Basic TraitTypes implementations/subclasses
 # -----------------------------------------------------------------------------