diff --git a/flask_restx/fields.py b/flask_restx/fields.py
index 97957f7f..328b437c 100644
--- a/flask_restx/fields.py
+++ b/flask_restx/fields.py
@@ -333,9 +333,11 @@ def is_attr(val):
         return [
             self.container.output(
                 idx,
-                val
-                if (isinstance(val, dict) or is_attr(val)) and not is_nested
-                else value,
+                (
+                    val
+                    if (isinstance(val, dict) or is_attr(val)) and not is_nested
+                    else value
+                ),
             )
             for idx, val in enumerate(value)
         ]
diff --git a/flask_restx/marshalling.py b/flask_restx/marshalling.py
index 6648f66f..df4bbecf 100644
--- a/flask_restx/marshalling.py
+++ b/flask_restx/marshalling.py
@@ -171,9 +171,11 @@ def __format_field(key, val):
         return (key, value)
 
     items = (
-        (k, marshal(data, v, skip_none=skip_none, ordered=ordered))
-        if isinstance(v, dict)
-        else __format_field(k, v)
+        (
+            (k, marshal(data, v, skip_none=skip_none, ordered=ordered))
+            if isinstance(v, dict)
+            else __format_field(k, v)
+        )
         for k, v in fields.items()
     )
 
diff --git a/flask_restx/namespace.py b/flask_restx/namespace.py
index 86b4b337..6d55fabe 100644
--- a/flask_restx/namespace.py
+++ b/flask_restx/namespace.py
@@ -253,9 +253,11 @@ def marshal_with(
         def wrapper(func):
             doc = {
                 "responses": {
-                    str(code): (description, [fields], kwargs)
-                    if as_list
-                    else (description, fields, kwargs)
+                    str(code): (
+                        (description, [fields], kwargs)
+                        if as_list
+                        else (description, fields, kwargs)
+                    )
                 },
                 "__mask__": kwargs.get(
                     "mask", True
diff --git a/flask_restx/schemas/__init__.py b/flask_restx/schemas/__init__.py
index 27b98660..84e4db17 100644
--- a/flask_restx/schemas/__init__.py
+++ b/flask_restx/schemas/__init__.py
@@ -4,6 +4,7 @@
 
 .. versionadded:: 0.12.1
 """
+
 import io
 import json
 
diff --git a/tasks.py b/tasks.py
index 4f14832a..34e357d5 100644
--- a/tasks.py
+++ b/tasks.py
@@ -125,9 +125,11 @@ def benchmark(
         "--benchmark-max-time={0}".format(max_time),
         "--benchmark-autosave" if save else None,
         "--benchmark-compare" if compare else None,
-        "--benchmark-histogram=histograms/{0:%Y%m%d-%H%M%S}".format(ts)
-        if histogram
-        else None,
+        (
+            "--benchmark-histogram=histograms/{0:%Y%m%d-%H%M%S}".format(ts)
+            if histogram
+            else None
+        ),
         "--benchmark-cprofile=tottime" if profile else None,
     )
     cmd = "pytest tests/benchmarks {0}".format(kwargs)
diff --git a/tests/test_inputs.py b/tests/test_inputs.py
index c6539b8c..eeac7e69 100644
--- a/tests/test_inputs.py
+++ b/tests/test_inputs.py
@@ -653,7 +653,7 @@ def test_valid_value_check(self, value):
     @pytest.mark.parametrize(
         "value",
         [
-            "coucou@not-found.fr",
+            "coucou@not-found.test",
             "me@localhost",
             "me@127.0.0.1",
             "me@127.1.2.3",