diff --git a/_test/test_bools.py b/_test/test_bools.py
index 2ca629c..bd6add6 100644
--- a/_test/test_bools.py
+++ b/_test/test_bools.py
@@ -1,16 +1,17 @@
+import io
+from typing import Any, Dict, List, Text  # NOQA
 
 import pytest
-import io
-import ruyaml  # NOQA
-from .roundtrip import round_trip, dedent
 
+import ruyaml  # NOQA
 from ruyaml import YAML
-from ruyaml.util import load_yaml_guess_indent
-from ruyaml.scalarbool import ScalarBoolean
 from ruyaml.comments import CommentedSeq
-from ruyaml.representer import RoundTripRepresenter, ScalarNode
 from ruyaml.constructor import RoundTripConstructor
-from typing import Text, Any, Dict, List  # NOQA
+from ruyaml.representer import RoundTripRepresenter, ScalarNode
+from ruyaml.scalarbool import ScalarBoolean
+from ruyaml.util import load_yaml_guess_indent
+
+from .roundtrip import dedent, round_trip
 
 
 class ScalarNodePositioned(ScalarNode):
@@ -18,14 +19,13 @@ class ScalarNodePositioned(ScalarNode):
 
 
 class ScalarBooleanStable(ScalarBoolean):
-
     def __new__(cls: Any, boolval, origrepr, anchor=None) -> Any:
         b = ScalarBoolean.__new__(cls, boolval, anchor=anchor)
         b.original_bool_repr = origrepr
         return b
 
 
-#def represent_list2(self, data):
+# def represent_list2(self, data):
 #    dedede
 # RoundTripRepresenter.add_representer(CommentedSeq, represent_list2)
 
@@ -36,7 +36,9 @@ class BetterRoundTripConstructor(RoundTripConstructor):
 
 class BetterRoundTripRepresenter(RoundTripRepresenter):
     def represent_bool(self, data, anchor=None):
-        ret = self.represent_scalar('tag:yaml.org,2002:bool', data.original_bool_repr, anchor=anchor)
+        ret = self.represent_scalar(
+            'tag:yaml.org,2002:bool', data.original_bool_repr, anchor=anchor
+        )
         return ret
 
     def TOTO_represent_sequence(self, tag, data):
@@ -46,8 +48,8 @@ def TOTO_represent_sequence(self, tag, data):
         local_block_seq_ident = -1
 
 
-#BetterRoundTripConstructor.add_constructor('tag:yaml.org,2002:bool', BetterRoundTripConstructor.construct_yaml_bool)
-#BetterRoundTripRepresenter.add_representer(ScalarBooleanStable, BetterRoundTripRepresenter.represent_bool)
+# BetterRoundTripConstructor.add_constructor('tag:yaml.org,2002:bool', BetterRoundTripConstructor.construct_yaml_bool)
+# BetterRoundTripRepresenter.add_representer(ScalarBooleanStable, BetterRoundTripRepresenter.represent_bool)
 
 
 def round_trip_stabler(
@@ -60,8 +62,8 @@ def round_trip_stabler(
     yaml = ruyaml.YAML()
     yaml.preserve_quotes = True
     yaml.preserve_bools = True
-    #yaml.Constructor = BetterRoundTripConstructor
-    #yaml.Representer = BetterRoundTripRepresenter
+    # yaml.Constructor = BetterRoundTripConstructor
+    # yaml.Representer = BetterRoundTripRepresenter
     data = yaml.load(doutp)
     buf = io.StringIO()
     yaml.dump(data, stream=buf)
@@ -70,7 +72,6 @@ def round_trip_stabler(
 
 
 class TestStability:
-
     def test_lowercase_boolean(self):
         round_trip(
             """
diff --git a/lib/ruyaml/main.py b/lib/ruyaml/main.py
index fd0a4fb..7cf16a7 100644
--- a/lib/ruyaml/main.py
+++ b/lib/ruyaml/main.py
@@ -243,9 +243,11 @@ def constructor(self):
         # type: () -> Any
         attr = '_' + sys._getframe().f_code.co_name
         if not hasattr(self, attr):
-            cnst = self.Constructor(preserve_quotes=self.preserve_quotes,
-                                    preserve_bools=self.preserve_bools,
-                                    loader=self)
+            cnst = self.Constructor(
+                preserve_quotes=self.preserve_quotes,
+                preserve_bools=self.preserve_bools,
+                loader=self,
+            )
             cnst.allow_duplicate_keys = self.allow_duplicate_keys
             setattr(self, attr, cnst)
         return getattr(self, attr)