diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index dfb062f..c982577 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -1,7 +1,7 @@
 ## Pull Request
 
 ### My patch is about
-- [ ] :bug: Bugfix 
+- [ ] :bug: Bugfix 
 - [ ] :arrow_up: Improvement
 - [ ] :pencil: Documentation
 - [ ] :heavy_check_mark: Tests
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 08757aa..7f84847 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -1,6 +1,11 @@
 name: 🎨 Linters
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - master
+      - main
+  pull_request:
 
 jobs:
   lint:
@@ -20,11 +25,11 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
-        pip install -U pip setuptools
+        pip install -U pip build wheel
         pip install -r dev-requirements.txt
     - name: Install the package
       run: |
-        python setup.py install
+        pip install .
     - name: Type checking (Mypy)
       run: |
         mypy kiss_headers
@@ -33,4 +38,4 @@ jobs:
         isort --check kiss_headers
     - name: Code format (Black)
       run: |
-        black --check --diff --target-version=py36 kiss_headers
+        black --check --diff --target-version=py37 kiss_headers
diff --git a/.github/workflows/pythonpublish.yml b/.github/workflows/pythonpublish.yml
index d5f3859..bf394f5 100644
--- a/.github/workflows/pythonpublish.yml
+++ b/.github/workflows/pythonpublish.yml
@@ -21,11 +21,11 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install setuptools wheel twine
+        pip install build wheel twine
     - name: Build and publish
       env:
-        TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
+        TWINE_USERNAME: __token__
         TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}
       run: |
-        python setup.py sdist bdist_wheel
+        python -m build
         twine upload dist/*
diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 9475546..deff995 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -1,6 +1,11 @@
 name: Tests
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - main
+      - master
+  pull_request:
 
 jobs:
   tests:
@@ -9,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9, "3.10", "3.11"]
+        python-version: [3.7, 3.8, 3.9, "3.10", "3.11", "3.12-dev"]
         os: [ubuntu-latest]
 
     steps:
@@ -20,11 +25,11 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
-        pip install -U pip setuptools
+        pip install -U pip build wheel
         pip install -r dev-requirements.txt
     - name: Install the package
       run: |
-        python setup.py install
+        pip install .
     - name: Run tests
       run: |
         pytest
diff --git a/README.md b/README.md
index 63a0aca..e7e19b5 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,7 @@ response = get(
 * Fully type-annotated.
 * Provide great auto-completion in Python interpreter or any capable IDE.
 * No dependencies. Never will be.
+* Support JSON in header value.
 * 90% test coverage.
 
 Plus all the features that you would expect from handling headers...
@@ -67,7 +68,7 @@ Plus all the features that you would expect from handling headers...
 
 ### ✨ Installation
 
-Whatever you like, use `pipenv` or `pip`, it simply works. Requires Python 3.6+ installed.
+Whatever you like, use `pipenv` or `pip`, it simply works. Requires Python 3.7+ installed.
 ```sh 
 pip install kiss-headers --upgrade
 ```
diff --git a/kiss_headers/__init__.py b/kiss_headers/__init__.py
index 89ef672..6876eea 100644
--- a/kiss_headers/__init__.py
+++ b/kiss_headers/__init__.py
@@ -36,8 +36,8 @@
 :license: MIT, see LICENSE for more details.
 """
 
-from kiss_headers.api import dumps, explain, get_polymorphic, parse_it
-from kiss_headers.builder import (
+from .api import dumps, explain, get_polymorphic, parse_it
+from .builder import (
     Accept,
     AcceptEncoding,
     AcceptLanguage,
@@ -87,9 +87,9 @@
     XFrameOptions,
     XXssProtection,
 )
-from kiss_headers.models import Attributes, Header, Headers, lock_output_type
-from kiss_headers.serializer import decode, encode
-from kiss_headers.version import VERSION, __version__
+from .models import Attributes, Header, Headers, lock_output_type
+from .serializer import decode, encode
+from .version import VERSION, __version__
 
 __all__ = (
     "dumps",
diff --git a/kiss_headers/api.py b/kiss_headers/api.py
index 6730e3c..1e4f18e 100644
--- a/kiss_headers/api.py
+++ b/kiss_headers/api.py
@@ -4,21 +4,23 @@
 from json import dumps as json_dumps, loads as json_loads
 from typing import Any, Iterable, List, Mapping, Optional, Tuple, Type, TypeVar, Union
 
-from kiss_headers.models import Header, Headers
-from kiss_headers.serializer import decode, encode
-from kiss_headers.structures import CaseInsensitiveDict
-from kiss_headers.utils import (
+from .builder import CustomHeader
+from .models import Header, Headers
+from .serializer import decode, encode
+from .structures import CaseInsensitiveDict
+from .utils import (
     class_to_header_name,
     decode_partials,
     extract_class_name,
     extract_encoded_headers,
     header_content_split,
     header_name_to_class,
+    is_content_json_object,
     is_legal_header_name,
     normalize_str,
 )
 
-T = TypeVar("T")
+T = TypeVar("T", bound=CustomHeader, covariant=True)
 
 
 def parse_it(raw_headers: Any) -> Headers:
@@ -88,12 +90,17 @@ def parse_it(raw_headers: Any) -> Headers:
     list_of_headers: List[Header] = []
 
     for head, content in revised_headers:
-
         # We should ignore when a illegal name is considered as an header. We avoid ValueError (in __init__ of Header)
         if is_legal_header_name(head) is False:
             continue
 
-        entries: List[str] = header_content_split(content, ",")
+        is_json_obj: bool = is_content_json_object(content)
+        entries: List[str]
+
+        if is_json_obj is False:
+            entries = header_content_split(content, ",")
+        else:
+            entries = [content]
 
         # Multiple entries are detected in one content at the only exception that its not IMAP header "Subject".
         if len(entries) > 1 and normalize_str(head) != "subject":
diff --git a/kiss_headers/builder.py b/kiss_headers/builder.py
index 01c910a..eab30b7 100644
--- a/kiss_headers/builder.py
+++ b/kiss_headers/builder.py
@@ -5,8 +5,8 @@
 from typing import Dict, List, Optional, Tuple, Union
 from urllib.parse import quote as url_quote, unquote as url_unquote
 
-from kiss_headers.models import Header
-from kiss_headers.utils import (
+from .models import Header
+from .utils import (
     class_to_header_name,
     header_content_split,
     prettify_header_name,
diff --git a/kiss_headers/models.py b/kiss_headers/models.py
index 68e323c..a909f52 100644
--- a/kiss_headers/models.py
+++ b/kiss_headers/models.py
@@ -1,13 +1,14 @@
 from copy import deepcopy
-from json import dumps
+from json import JSONDecodeError, dumps, loads
 from typing import Dict, Iterable, Iterator, List, Optional, Tuple, Type, Union
 
-from kiss_headers.structures import AttributeBag, CaseInsensitiveDict
-from kiss_headers.utils import (
+from .structures import AttributeBag, CaseInsensitiveDict
+from .utils import (
     escape_double_quote,
     extract_comments,
     header_content_split,
     header_name_to_class,
+    is_content_json_object,
     is_legal_header_name,
     normalize_list,
     normalize_str,
@@ -54,7 +55,29 @@ def __init__(self, name: str, content: str):
         self._pretty_name: str = prettify_header_name(self._name)
         self._content: str = content
 
-        self._members: List[str] = header_content_split(self._content, ";")
+        self._members: List[str]
+
+        if is_content_json_object(self._content):
+            try:
+                payload = loads(self._content)
+            except JSONDecodeError as e:
+                raise ValueError(
+                    f"Header '{self._name}' contain an invalid JSON value."
+                ) from e
+
+            if isinstance(payload, list):
+                self._members = payload
+            elif isinstance(payload, dict):
+                self._members = []
+                for k, v in payload.items():
+                    if v is not None:
+                        self._members.append(f"{str(k)}={str(v)}")
+                    else:
+                        self._members.append(str(k))
+            else:
+                raise ValueError(f"Header '{self._name}' is malformed.")
+        else:
+            self._members = header_content_split(self._content, ";")
 
         self._attrs: Attributes = Attributes(self._members)
 
@@ -264,7 +287,6 @@ def __add__(self, other: Union[str, "Header"]) -> Union["Header", "Headers"]:
             )
 
         if isinstance(other, Header):
-
             headers = Headers()
             headers += self
             headers += other
@@ -644,6 +666,8 @@ class Headers(object):
 
     from_: Union[Header, List[Header]]
 
+    report_to: Union[Header, List[Header]]
+
     def __init__(self, *headers: Union[List[Header], Header]):
         """
         :param headers: Initial list of header. Can be empty.
@@ -801,11 +825,9 @@ def __setitem__(self, key: str, value: str) -> None:
 
         # Permit to detect multiple entries.
         if normalize_str(key) != "subject":
-
             entries: List[str] = header_content_split(value, ",")
 
             if len(entries) > 1:
-
                 for entry in entries:
                     self._headers.append(Header(key, entry))
 
@@ -878,7 +900,6 @@ def __repr__(self) -> str:
         result: List[str] = []
 
         for header_name in self.keys():
-
             r = self.get(header_name)
 
             if not r:
@@ -1193,7 +1214,6 @@ def __init__(self, members: List[str]):
         self._bag: AttributeBag = CaseInsensitiveDict()
 
         for member, index in zip(members, range(0, len(members))):
-
             if member == "":
                 continue
 
@@ -1255,11 +1275,9 @@ def __eq__(self, other: object) -> bool:
         list_check: List[Tuple[int, str, Optional[str]]] = []
 
         for index_a, key_a, value_a in list_repr_a:
-
             key_a = normalize_str(key_a)
 
             for index_b, key_b, value_b in list_repr_b:
-
                 key_b = normalize_str(key_b)
 
                 if (
@@ -1267,7 +1285,6 @@ def __eq__(self, other: object) -> bool:
                     and value_a == value_b
                     and (index_a, key_a, key_b) not in list_check
                 ):
-
                     list_check.append((index_a, key_a, key_b))
 
         return len(list_check) == len(list_repr_a)
@@ -1358,7 +1375,6 @@ def remove(
         freed_indexes: List[int] = []
 
         if index is not None:
-
             if with_value is not None:
                 raise ValueError(
                     "Cannot set both index and with_value in the remove method."
@@ -1373,9 +1389,7 @@ def remove(
             freed_indexes.append(self._bag[key][1].pop(pos))
 
         if index is None:
-
             if with_value is not None:
-
                 for index_, value_ in zip(self._bag[key][1], self._bag[key][0]):
                     if with_value is True and value_ is not None:
                         freed_indexes.append(index_)
@@ -1397,7 +1411,6 @@ def remove(
             del self._bag[key]
 
         for attr in self._bag:
-
             values, indexes = self._bag[attr]
             max_freed_index: int = max(freed_indexes)
 
diff --git a/kiss_headers/serializer.py b/kiss_headers/serializer.py
index 022b889..e554907 100644
--- a/kiss_headers/serializer.py
+++ b/kiss_headers/serializer.py
@@ -1,6 +1,6 @@
 from typing import Dict, List, Optional, Union
 
-from kiss_headers.models import Header, Headers
+from .models import Header, Headers
 
 
 def encode(headers: Headers) -> Dict[str, List[Dict]]:
@@ -10,14 +10,12 @@ def encode(headers: Headers) -> Dict[str, List[Dict]]:
     result: Dict[str, List[Dict]] = dict()
 
     for header in headers:
-
         if header.name not in result:
             result[header.name] = list()
 
         encoded_header: Dict[str, Union[Optional[str], List[str]]] = dict()
 
         for attribute, value in header:
-
             if attribute not in encoded_header:
                 encoded_header[attribute] = value
                 continue
diff --git a/kiss_headers/utils.py b/kiss_headers/utils.py
index c76f4f7..5647270 100644
--- a/kiss_headers/utils.py
+++ b/kiss_headers/utils.py
@@ -103,7 +103,6 @@ def header_content_split(string: str, delimiter: str) -> List[str]:
     result: List[str] = [""]
 
     for letter, index in zip(string, range(0, len(string))):
-
         if letter == '"':
             in_double_quote = not in_double_quote
 
@@ -126,7 +125,6 @@ def header_content_split(string: str, delimiter: str) -> List[str]:
             }
 
         if not in_double_quote:
-
             if not in_value and letter == "=":
                 in_value = True
             elif letter == ";" and in_value:
@@ -138,7 +136,6 @@ def header_content_split(string: str, delimiter: str) -> List[str]:
         if letter == delimiter and (
             (in_value or in_double_quote or in_parenthesis or is_on_a_day) is False
         ):
-
             result[-1] = result[-1].lstrip().rstrip()
             result.append("")
 
@@ -453,3 +450,14 @@ def escape_double_quote(content: str) -> str:
     'UTF\\"-8'
     """
     return unescape_double_quote(content).replace('"', r"\"")
+
+
+def is_content_json_object(content: str) -> bool:
+    """
+    Sometime, you may receive a header that hold a JSON list or object.
+    This function detect it.
+    """
+    content = content.strip()
+    return (content.startswith("{") and content.endswith("}")) or (
+        content.startswith("[") and content.endswith("]")
+    )
diff --git a/kiss_headers/version.py b/kiss_headers/version.py
index 432201b..06f9e53 100644
--- a/kiss_headers/version.py
+++ b/kiss_headers/version.py
@@ -2,5 +2,5 @@
 Expose version
 """
 
-__version__ = "2.3.1"
+__version__ = "2.4.0"
 VERSION = __version__.split(".")
diff --git a/mkdocs.yml b/mkdocs.yml
index 580574c..6292859 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -1,6 +1,6 @@
 site_name: Kiss-Headers
 site_description: Python package for object oriented headers, HTTP/1.1 style. Parse headers to objects.
-site_url: https://kiss-headers.tech/
+site_url: https://ousret.github.io/kiss-headers
 
 theme:
     name: 'material'
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..5ac57ee
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,84 @@
+[build-system]
+requires = ["hatchling>=1.6.0,<2"]
+build-backend = "hatchling.build"
+
+[project]
+name = "kiss-headers"
+description = "Object-oriented HTTP and IMAP (structured) headers."
+readme = "README.md"
+license-files = { paths = ["LICENSE"] }
+license = "MIT"
+keywords = ["headers", "http", "mail", "text", "imap", "header", "https", "imap4"]
+authors = [
+  {name = "Ahmed R. TAHRI", email="ahmed.tahri@cloudnursery.dev"},
+]
+maintainers = [
+  {name = "Ahmed R. TAHRI", email="ahmed.tahri@cloudnursery.dev"},
+]
+classifiers = [
+    "License :: OSI Approved :: MIT License",
+    "Intended Audience :: Developers",
+    "Development Status :: 5 - Production/Stable",
+    "Topic :: Communications :: Email",
+    "Topic :: Internet :: WWW/HTTP",
+    "Topic :: Internet :: WWW/HTTP :: Dynamic Content :: Content Management System",
+    "Environment :: Web Environment",
+    "Topic :: Software Development :: Libraries :: Python Modules",
+    "Operating System :: OS Independent",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3 :: Only",
+    "Topic :: Utilities",
+    "Programming Language :: Python :: Implementation :: PyPy",
+]
+requires-python = ">=3.7"
+dynamic = ["version"]
+
+[project.urls]
+"Documentation" = "https://ousret.github.io/kiss-headers"
+"Code" = "https://github.com/ousret/kiss-headers"
+"Issue tracker" = "https://github.com/ousret/kiss-headers/issues"
+
+[tool.hatch.version]
+path = "kiss_headers/version.py"
+
+[tool.hatch.build.targets.sdist]
+include = [
+    "/docs",
+    "/kiss_headers",
+    "/tests",
+    "/dev-requirements.txt",
+    "/README.md",
+    "/LICENSE",
+    "/setup.cfg",
+]
+
+[tool.hatch.build.targets.wheel]
+packages = [
+    "kiss_headers/",
+]
+
+[tool.isort]
+profile = "black"
+src_paths = ["kiss_headers", "tests"]
+honor_noqa = true
+combine_as_imports = true
+force_grid_wrap = 0
+include_trailing_comma = true
+known_first_party = "kiss_headers,tests"
+line_length = 88
+multi_line_output = 3
+
+[tool.pytest.ini_options]
+addopts = "--cov=kiss_headers --doctest-modules --cov-report=term-missing -rxXs"
+doctest_optionflags = "NORMALIZE_WHITESPACE ELLIPSIS"
+minversion = "6.2"
+testpaths = ["tests", "kiss_headers"]
+
+[tool.mypy]
+disallow_untyped_defs = true
diff --git a/scripts/check b/scripts/check
index 085c75e..51e2185 100755
--- a/scripts/check
+++ b/scripts/check
@@ -8,7 +8,7 @@ export SOURCE_FILES="kiss_headers tests"
 
 set -x
 
-${PREFIX}black --check --diff --target-version=py36 $SOURCE_FILES
+${PREFIX}black --check --diff --target-version=py37 $SOURCE_FILES
 ${PREFIX}mypy kiss_headers
-${PREFIX}isort --check --diff --project=kiss_headers --recursive $SOURCE_FILES
+${PREFIX}isort --check --diff --project=kiss_headers  $SOURCE_FILES
 ${PREFIX}pytest
diff --git a/scripts/install b/scripts/install
index 3664869..ceadfd1 100755
--- a/scripts/install
+++ b/scripts/install
@@ -11,7 +11,7 @@ else
   python -m venv venv
 fi
 
-${PREFIX}python -m pip install -U pip setuptools
-${PREFIX}python -m pip install -r requirements.txt
+${PREFIX}python -m pip install -U pip build wheel
+${PREFIX}python -m pip install -r dev-requirements.txt
 
 set +x
diff --git a/scripts/lint b/scripts/lint
index 4fef19d..516e7ec 100755
--- a/scripts/lint
+++ b/scripts/lint
@@ -7,5 +7,5 @@ fi
 export SOURCE_FILES="kiss_headers tests"
 
 set -x
-${PREFIX}black --diff --target-version=py36 $SOURCE_FILES
-${PREFIX}isort --project=kiss_headers --recursive --apply $SOURCE_FILES
+${PREFIX}black --target-version=py37 $SOURCE_FILES
+${PREFIX}isort --project=kiss_headers $SOURCE_FILES
diff --git a/setup.cfg b/setup.cfg
index 6046732..131a4f8 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,18 +1,3 @@
 [flake8]
 ignore = W503, E203, B305, E501, F401, E128, E402, E731, F821, Q000
 max-line-length = 88
-
-[mypy]
-disallow_untyped_defs = True
-
-[tool:isort]
-combine_as_imports = True
-force_grid_wrap = 0
-include_trailing_comma = True
-known_first_party = kiss_headers,tests
-line_length = 88
-multi_line_output = 3
-
-[tool:pytest]
-addopts = --cov=kiss_headers --doctest-modules --cov-report=term-missing -rxXs
-doctest_optionflags= NORMALIZE_WHITESPACE ELLIPSIS
diff --git a/setup.py b/setup.py
deleted file mode 100644
index e641df1..0000000
--- a/setup.py
+++ /dev/null
@@ -1,80 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-import io
-import os
-
-from setuptools import find_packages, setup
-from re import search
-
-
-def get_version():
-    with open("kiss_headers/version.py") as version_file:
-        return search(
-            r"""__version__\s+=\s+(['"])(?P<version>.+?)\1""", version_file.read()
-        ).group("version")
-
-
-# Package meta-data.
-NAME = "kiss-headers"
-DESCRIPTION = "Python package for object oriented headers, HTTP/1.1 style. Parser and serializer for http headers."
-URL = "https://github.com/ousret/kiss-headers"
-EMAIL = "ahmed.tahri@cloudnursery.dev"
-AUTHOR = "Ahmed TAHRI @Ousret"
-REQUIRES_PYTHON = ">=3.6"
-VERSION = get_version()
-
-EXTRAS = {}
-
-here = os.path.abspath(os.path.dirname(__file__))
-
-try:
-    with io.open(os.path.join(here, "README.md"), encoding="utf-8") as f:
-        long_description = "\n" + f.read()
-except FileNotFoundError:
-    long_description = DESCRIPTION
-
-setup(
-    name=NAME,
-    version=VERSION,
-    description=DESCRIPTION,
-    long_description=long_description,
-    long_description_content_type="text/markdown",
-    author=AUTHOR,
-    author_email=EMAIL,
-    python_requires=REQUIRES_PYTHON,
-    url=URL,
-    project_urls={
-        "Documentation": "https://ousret.github.io/kiss-headers",
-        "Source": "https://github.com/Ousret/kiss-headers",
-        "Issue tracker": "https://github.com/Ousret/kiss-headers/issues",
-    },
-    keywords=["headers", "http", "mail", "text", "imap", "header", "https", "imap4"],
-    packages=find_packages(exclude=["tests", "*.tests", "*.tests.*", "tests.*"]),
-    package_data={"kiss_headers": ["py.typed"]},
-    install_requires=[],  # We shall not require anything. This will remain the same.
-    extras_require=EXTRAS,
-    include_package_data=True,
-    license="MIT",
-    classifiers=[
-        "License :: OSI Approved :: MIT License",
-        "Intended Audience :: Developers",
-        "Development Status :: 5 - Production/Stable",
-        "Topic :: Communications :: Email",
-        "Topic :: Internet :: WWW/HTTP",
-        "Topic :: Internet :: WWW/HTTP :: Dynamic Content :: Content Management System",
-        "Environment :: Web Environment",
-        "Topic :: Software Development :: Libraries :: Python Modules",
-        "Operating System :: OS Independent",
-        "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
-        "Programming Language :: Python :: 3.8",
-        "Programming Language :: Python :: 3.9",
-        "Programming Language :: Python :: 3.10",
-        "Programming Language :: Python :: 3.11",
-        "Programming Language :: Python :: 3 :: Only",
-        "Topic :: Utilities",
-        "Programming Language :: Python :: Implementation :: PyPy",
-    ],
-)
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_attributes.py b/tests/test_attributes.py
index 5b0f0f0..3d214ef 100644
--- a/tests/test_attributes.py
+++ b/tests/test_attributes.py
@@ -24,7 +24,6 @@ def test_eq(self):
             self.assertNotEqual(attr_a, attr_e)
 
     def test_esc_double_quote(self):
-
         with self.subTest(
             "Ensure that the double quote character is handled correctly."
         ):
diff --git a/tests/test_builder.py b/tests/test_builder.py
index 72cf34d..4f33035 100644
--- a/tests/test_builder.py
+++ b/tests/test_builder.py
@@ -18,19 +18,16 @@
 
 class MyBuilderTestCase(unittest.TestCase):
     def test_custom_header_expect(self):
-
         with self.assertRaises(NotImplementedError):
             k = CustomHeader("Should absolutely not work !")
 
     def test_content_type(self):
-
         self.assertEqual(
             repr(ContentType("application/json", charset="utf-8")),
             'Content-Type: application/json; charset="UTF-8"',
         )
 
     def test_set_cookie(self):
-
         dt = datetime.now()
 
         self.assertEqual(
@@ -41,18 +38,15 @@ def test_set_cookie(self):
         )
 
     def test_content_length(self):
-
         self.assertEqual(repr(ContentLength(1881)), "Content-Length: 1881")
 
     def test_content_disposition(self):
-
         self.assertEqual(
             repr(ContentDisposition("attachment", filename="test-file.json")),
             'Content-Disposition: attachment; filename="test-file.json"',
         )
 
     def test_value_error_builder(self):
-
         with self.assertRaises(ValueError):
             CrossOriginResourcePolicy("policy-not-known-yet")
 
@@ -66,7 +60,6 @@ def test_value_error_builder(self):
             Allow("DOES-NOT-EXIST-HTTP-VERB")
 
     def test_verify_always_gmt(self):
-
         self.assertTrue(repr(Date(datetime.now())).endswith("GMT"))
 
 
diff --git a/tests/test_builder_create.py b/tests/test_builder_create.py
index 2037e97..601efde 100644
--- a/tests/test_builder_create.py
+++ b/tests/test_builder_create.py
@@ -62,7 +62,6 @@
 
 class MyBuilderCreationTestCase(unittest.TestCase):
     def test_replicate_raw_from_objects_request(self):
-
         headers = (
             Host("developer.mozilla.org")
             + UserAgent(
@@ -88,7 +87,6 @@ def test_replicate_raw_from_objects_request(self):
         self.assertEqual(parse_it(RAW_HEADERS_MOZILLA), headers)
 
     def test_replicate_raw_from_objects(self):
-
         headers = (
             Header("Accept-Ch", "DPR")
             + Header("Accept-Ch-Lifetime", "2592000")
diff --git a/tests/test_explain.py b/tests/test_explain.py
index 8be7423..03405b7 100644
--- a/tests/test_explain.py
+++ b/tests/test_explain.py
@@ -20,7 +20,6 @@
 
 class MyExplainTestCase(unittest.TestCase):
     def test_explain_from_objects(self):
-
         headers = (
             Header("Accept-Ch", "DPR")
             + Header("Accept-Ch-Lifetime", "2592000")
diff --git a/tests/test_header_operation.py b/tests/test_header_operation.py
index 166f340..f57cc1c 100644
--- a/tests/test_header_operation.py
+++ b/tests/test_header_operation.py
@@ -27,7 +27,6 @@ def test_isub_adjective(self):
         self.assertEqual('charset="utf-8"', str(content_type))
 
     def test_iadd_adjective(self):
-
         content_type = Header("Content-Type", 'charset="utf-8"')
 
         self.assertNotIn("text/html", content_type)
@@ -50,7 +49,6 @@ def test_subtract_adjective(self):
         self.assertEqual('charset="utf-8"', str(content_type))
 
     def test_add_adjective(self):
-
         content_type = Header("Content-Type", 'charset="utf-8"')
 
         self.assertNotIn("text/html", content_type)
@@ -105,7 +103,6 @@ def test_complex_second_attr_removal(self):
         self.assertEqual('text/html; charset="utf-8"', str(content_type))
 
     def test_simple_attr_add(self):
-
         content_type = Header("Content-Type", 'text/html; charset="utf-8"')
 
         self.assertNotIn("format", content_type)
@@ -119,7 +116,6 @@ def test_simple_attr_add(self):
         self.assertEqual('text/html; charset="utf-8"; format="flowed"', content_type)
 
     def test_contain_space_delimiter(self):
-
         authorization = Header("Authorization", "Bearer mysupersecrettoken")
 
         self.assertIn("Bearer", authorization)
@@ -142,7 +138,6 @@ def test_illegal_delitem_operation(self):
                 del content_type["text/html"]
 
     def test_attrs_access_case_insensitive(self):
-
         content_type = Header("Content-Type", 'text/html; charset="utf-8"')
 
         with self.subTest("Verify that attrs can be accessed no matter case"):
diff --git a/tests/test_header_order.py b/tests/test_header_order.py
index 4c9bfdc..0655ba3 100644
--- a/tests/test_header_order.py
+++ b/tests/test_header_order.py
@@ -17,7 +17,6 @@ def test_insertion_in_ordered_header(self):
         self.assertEqual(["a", "b", "ppp", "h", "h", "z"], header.attrs)
 
     def test_pop_in_ordered_header(self):
-
         header = Header("Content-Type", "a; b=k; h; h; z=0")
 
         key, value = header.pop(2)
diff --git a/tests/test_headers.py b/tests/test_headers.py
index bd7ab39..43f9363 100644
--- a/tests/test_headers.py
+++ b/tests/test_headers.py
@@ -4,8 +4,17 @@
 
 
 class MyKissHeaderTest(unittest.TestCase):
-    def test_invalid_eq(self):
+    def test_json_header(self):
+        header = Header(
+            "Report-To",
+            '{"endpoints":[{"url":"https://a.nel.cloudflare.com/report/v3?s=zhnRFonTa%2FAOS8x%2BTZXZBDr5B0k7E7rziICyCRD5SVCtz106%2FlbzKGHKLwXpAC1XUZ5Nb5SQBuoI336MkB%2BzhxjictL4oc6wjku7aFfGBCi5rMi5Z5LPYVMDPUnhFDymbNiE7wc9"}],"group":"cf-nel","max_age":604800}',
+        )
+
+        assert "endpoints" in header
+        assert "group" in header
+        assert header.group == "cf-nel"
 
+    def test_invalid_eq(self):
         header = Header(
             "Message-ID", "<455DADE4FB733C4C8F62EB4CEB36D8DE05037EA94F@johndoe>"
         )
@@ -14,7 +23,6 @@ def test_invalid_eq(self):
             k = header == 1
 
     def test_simple_eq(self):
-
         self.assertEqual(
             Header(
                 "Message-ID", "<455DADE4FB733C4C8F62EB4CEB36D8DE05037EA94F@johndoe>"
@@ -49,7 +57,6 @@ def test_simple_eq(self):
         )
 
     def test_attribute_access_exist(self):
-
         self.assertIn(
             "charset",
             Header(
@@ -84,7 +91,6 @@ def test_attribute_not_in(self):
         )
 
     def test_access_attribute(self):
-
         self.assertEqual(
             Header(
                 "Content-Type",
diff --git a/tests/test_headers_from_string.py b/tests/test_headers_from_string.py
index 3aa57f1..9fa33ec 100644
--- a/tests/test_headers_from_string.py
+++ b/tests/test_headers_from_string.py
@@ -41,27 +41,23 @@
 
 
 class MyKissHeadersFromStringTest(unittest.TestCase):
-
     headers: Headers
 
     def setUp(self) -> None:
         MyKissHeadersFromStringTest.headers = parse_it(RAW_HEADERS)
 
     def test_decode_partials(self):
-
         self.assertEqual(
             [("Subject", "pöstal")],
             decode_partials([("Subject", "=?iso-8859-1?q?p=F6stal?=")]),
         )
 
     def test_bytes_headers(self):
-
         self.assertEqual(
             MyKissHeadersFromStringTest.headers, parse_it(RAW_HEADERS.encode("utf-8"))
         )
 
     def test_two_headers_eq(self):
-
         self.assertEqual(MyKissHeadersFromStringTest.headers, parse_it(RAW_HEADERS))
 
         self.assertNotEqual(
@@ -69,7 +65,6 @@ def test_two_headers_eq(self):
         )
 
     def test_headers_get_has(self):
-
         self.assertIsNone(MyKissHeadersFromStringTest.headers.get("received"))
         self.assertFalse(MyKissHeadersFromStringTest.headers.has("received"))
 
@@ -78,7 +73,6 @@ def test_headers_get_has(self):
         )
 
     def test_repr_dict(self):
-
         dict_ = MyKissHeadersFromStringTest.headers.to_dict()
 
         self.assertIn("set-cookie", dict_)
@@ -98,7 +92,6 @@ def test_repr_dict(self):
         )
 
     def test_repr_str(self):
-
         self.assertEqual(RAW_HEADERS, repr(MyKissHeadersFromStringTest.headers))
 
         self.assertEqual(RAW_HEADERS, str(MyKissHeadersFromStringTest.headers))
@@ -113,7 +106,6 @@ def test_repr_str(self):
         )
 
     def test_control_basis_exist(self):
-
         self.assertEqual("DPR", MyKissHeadersFromStringTest.headers.accept_ch)
 
         self.assertEqual(3, len(MyKissHeadersFromStringTest.headers.set_cookie))
@@ -134,7 +126,6 @@ def test_control_basis_exist(self):
         )
 
     def test_control_first_line_not_header(self):
-
         headers = parse_it(RAW_HEADERS_MOZILLA)
 
         self.assertEqual(17, len(headers))
diff --git a/tests/test_polymorphic.py b/tests/test_polymorphic.py
index ed50108..acbcd26 100644
--- a/tests/test_polymorphic.py
+++ b/tests/test_polymorphic.py
@@ -5,7 +5,6 @@
 
 class MyPolymorphicTestCase(unittest.TestCase):
     def test_get_polymorphic(self):
-
         headers = parse_it(
             """accept-ch: DPR
 accept-ch-lifetime: 2592000
diff --git a/tests/test_serializer.py b/tests/test_serializer.py
index ee8ab98..013ab34 100644
--- a/tests/test_serializer.py
+++ b/tests/test_serializer.py
@@ -43,12 +43,10 @@ def test_encode_decode(self):
         )
 
     def test_decode_failure(self):
-
         with self.assertRaises(ValueError):
             decode({"Not Decodable": "X"})  # type: ignore
 
     def test_json_with_indent(self):
-
         headers: Headers = parse_it(RAW_HEADERS)
         json_headers: str = dumps(headers, indent=4)
 
diff --git a/tests/test_with_http_request.py b/tests/test_with_http_request.py
index daab32f..1b3ab66 100644
--- a/tests/test_with_http_request.py
+++ b/tests/test_with_http_request.py
@@ -7,15 +7,12 @@
 
 
 class MyHttpTestKissHeaders(unittest.TestCase):
-
     HTTPBIN_GET: Optional[Response] = None
 
     def setUp(self) -> None:
-
         MyHttpTestKissHeaders.HTTPBIN_GET = get("https://httpbin.org/get")
 
     def test_httpbin_raw_headers(self):
-
         headers = parse_it(
             """Host: developer.mozilla.org
 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:50.0) Gecko/20100101 Firefox/50.0
@@ -47,7 +44,6 @@ def test_httpbin_raw_headers(self):
         self.assertEqual("0", headers.cache_control.max_age)
 
     def test_parse_response(self):
-
         headers = parse_it(MyHttpTestKissHeaders.HTTPBIN_GET)
 
         self.assertEqual(headers.content_type, "application/json")
@@ -60,7 +56,6 @@ def test_parse_response(self):
             headers.user_agent
 
     def test_httpbin_get(self):
-
         response_headers = MyHttpTestKissHeaders.HTTPBIN_GET.headers
         headers = parse_it(response_headers)
 
@@ -74,7 +69,6 @@ def test_httpbin_get(self):
             headers.user_agent
 
     def test_httpbin_freeform(self):
-
         response_headers = get(
             "https://httpbin.org/response-headers",
             params={
@@ -98,7 +92,6 @@ def test_httpbin_freeform(self):
         self.assertIn("application/kiss", headers.freeform)
 
     def test_httpbin_with_our_headers(self):
-
         response = get(
             "https://httpbin.org/bearer",
             headers=Headers(Authorization("Bearer", "qwerty")),