diff --git a/.flake8 b/.flake8
new file mode 100644
index 0000000..2bcd70e
--- /dev/null
+++ b/.flake8
@@ -0,0 +1,2 @@
+[flake8]
+max-line-length = 88
diff --git a/.therapist.yml b/.therapist.yml
new file mode 100644
index 0000000..5a3caa8
--- /dev/null
+++ b/.therapist.yml
@@ -0,0 +1,9 @@
+actions:
+  black:
+    run: black --check --diff {files}
+    fix: black {files}
+    include: "*.py"
+
+  flake8:
+    run: flake8 {files}
+    include: "*.py"
diff --git a/README.rst b/README.rst
index 8359364..22b75d5 100644
--- a/README.rst
+++ b/README.rst
@@ -14,6 +14,8 @@ django-cache-memoize
    :alt: Code Coverage
    :target: https://codecov.io/gh/peterbe/django-cache-memoize
 
+.. image:: https://img.shields.io/badge/code%20style-black-000000.svg
+  :target: https://github.com/ambv/black
 
 Django utility for a memoization decorator that uses the Django cache framework.
 
@@ -387,3 +389,39 @@ The most basic thing is to clone the repo and run:
 
     pip install -e ".[dev]"
     tox
+
+
+Code style is all black
+~~~~~~~~~~~~~~~~~~~~~~~
+
+All code has to be formatted with `Black <https://pypi.org/project/black/>`_
+and the best tool for checking this is
+`therapist <https://pypi.org/project/therapist/>`_ since it can help you run
+all, help you fix things, and help you make sure linting is passing before
+you git commit. This project also uses ``flake8`` to check other things
+Black can't check.
+
+To check linting with ``tox`` use:
+
+.. code:: bash
+
+    tox -e lint-py36
+
+To install the ``therapist`` pre-commit hook simply run:
+
+.. code:: bash
+
+    therapist install
+
+When you run ``therapist run`` it will only check the files you've touched.
+To run it for all files use:
+
+.. code:: bash
+
+    therapist run --use-tracked-files
+
+And to fix all/any issues run:
+
+.. code:: bash
+
+    therapist run --use-tracked-files --fix
diff --git a/docs/conf.py b/docs/conf.py
index eceb66f..bf493f6 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -34,30 +34,30 @@
 extensions = []
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ["_templates"]
 
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
 #
 # source_suffix = ['.rst', '.md']
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = 'django-cache-memoize'
-copyright = '2017, Peter Bengtsson'
-author = 'Peter Bengtsson'
+project = "django-cache-memoize"
+copyright = "2017, Peter Bengtsson"
+author = "Peter Bengtsson"
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
 # The short X.Y version.
-version = ''
+version = ""
 # The full version, including alpha/beta/rc tags.
-release = ''
+release = ""
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -69,10 +69,10 @@
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This patterns also effect to html_static_path and html_extra_path
-exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+exclude_patterns = ["_build", "Thumbs.db", ".DS_Store"]
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = "sphinx"
 
 # If true, `todo` and `todoList` produce output, else they produce nothing.
 todo_include_todos = False
@@ -83,7 +83,7 @@
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-html_theme = 'alabaster'
+html_theme = "alabaster"
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
@@ -94,7 +94,7 @@
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static']
+html_static_path = ["_static"]
 
 # Custom sidebar templates, must be a dictionary that maps document names
 # to template names.
@@ -102,9 +102,9 @@
 # This is required for the alabaster theme
 # refs: http://alabaster.readthedocs.io/en/latest/installation.html#sidebars
 html_sidebars = {
-    '**': [
-        'relations.html',  # needs 'show_related': True theme option to display
-        'searchbox.html',
+    "**": [
+        "relations.html",  # needs 'show_related': True theme option to display
+        "searchbox.html",
     ]
 }
 
@@ -112,7 +112,7 @@
 # -- Options for HTMLHelp output ------------------------------------------
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'django-cache-memoizedoc'
+htmlhelp_basename = "django-cache-memoizedoc"
 
 
 # -- Options for LaTeX output ---------------------------------------------
@@ -121,15 +121,12 @@
     # The paper size ('letterpaper' or 'a4paper').
     #
     # 'papersize': 'letterpaper',
-
     # The font size ('10pt', '11pt' or '12pt').
     #
     # 'pointsize': '10pt',
-
     # Additional stuff for the LaTeX preamble.
     #
     # 'preamble': '',
-
     # Latex figure (float) alignment
     #
     # 'figure_align': 'htbp',
@@ -139,8 +136,13 @@
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
 latex_documents = [
-    (master_doc, 'django-cache-memoize.tex', 'django-cache-memoize Documentation',
-     'Peter Bengtsson', 'manual'),
+    (
+        master_doc,
+        "django-cache-memoize.tex",
+        "django-cache-memoize Documentation",
+        "Peter Bengtsson",
+        "manual",
+    )
 ]
 
 
@@ -149,8 +151,13 @@
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
 man_pages = [
-    (master_doc, 'django-cache-memoize', 'django-cache-memoize Documentation',
-     [author], 1)
+    (
+        master_doc,
+        "django-cache-memoize",
+        "django-cache-memoize Documentation",
+        [author],
+        1,
+    )
 ]
 
 
@@ -160,10 +167,13 @@
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
 texinfo_documents = [
-    (master_doc, 'django-cache-memoize', 'django-cache-memoize Documentation',
-     author, 'django-cache-memoize', 'One line description of project.',
-     'Miscellaneous'),
+    (
+        master_doc,
+        "django-cache-memoize",
+        "django-cache-memoize Documentation",
+        author,
+        "django-cache-memoize",
+        "One line description of project.",
+        "Miscellaneous",
+    )
 ]
-
-
-
diff --git a/setup.py b/setup.py
index 5103a14..9fbc057 100644
--- a/setup.py
+++ b/setup.py
@@ -5,33 +5,31 @@
 
 
 setup(
-    name='django-cache-memoize',
-    version='0.1.4',
+    name="django-cache-memoize",
+    version="0.1.4",
     description=(
-        'Django utility for a memoization decorator that uses the Django '
-        'cache framework.'
+        "Django utility for a memoization decorator that uses the Django "
+        "cache framework."
     ),
-    long_description=open(path.join(_here, 'README.rst')).read(),
-    author='Peter Bengtsson',
-    author_email='mail@peterbe.com',
-    license='MPL 2.0',
-    url='https://github.com/peterbe/django-cache-memoize',
-    packages=find_packages(where='src'),
-    package_dir={'': 'src'},
+    long_description=open(path.join(_here, "README.rst")).read(),
+    author="Peter Bengtsson",
+    author_email="mail@peterbe.com",
+    license="MPL 2.0",
+    url="https://github.com/peterbe/django-cache-memoize",
+    packages=find_packages(where="src"),
+    package_dir={"": "src"},
     classifiers=[
-        'Development Status :: 5 - Production/Stable',
-        'Environment :: Web Environment :: Mozilla',
-        'Framework :: Django',
-        'Intended Audience :: Developers',
-        'License :: OSI Approved :: Mozilla Public License 2.0 (MPL 2.0)',
-        'License :: OSI Approved :: MIT License',
-        'Programming Language :: Python :: 2.7',
-        'Programming Language :: Python :: 3',
-        'Topic :: Internet :: WWW/HTTP',
+        "Development Status :: 5 - Production/Stable",
+        "Environment :: Web Environment :: Mozilla",
+        "Framework :: Django",
+        "Intended Audience :: Developers",
+        "License :: OSI Approved :: Mozilla Public License 2.0 (MPL 2.0)",
+        "License :: OSI Approved :: MIT License",
+        "Programming Language :: Python :: 2.7",
+        "Programming Language :: Python :: 3",
+        "Topic :: Internet :: WWW/HTTP",
     ],
-    keywords=['django', 'memoize', 'cache', 'decorator'],
+    keywords=["django", "memoize", "cache", "decorator"],
     zip_safe=False,
-    extras_require={
-        'dev': ['flake8', 'tox', 'twine'],
-    }
+    extras_require={"dev": ["flake8", "tox", "twine", "therapist", "black"]},
 )
diff --git a/src/cache_memoize/__init__.py b/src/cache_memoize/__init__.py
index ed63516..411bfc3 100644
--- a/src/cache_memoize/__init__.py
+++ b/src/cache_memoize/__init__.py
@@ -82,22 +82,23 @@ def callmeonce(arg1):
     """
 
     if args_rewrite is None:
+
         def noop(*args):
             return args
+
         args_rewrite = noop
 
     cache = caches[cache_alias]
 
     def decorator(func):
-
         def _make_cache_key(*args, **kwargs):
-            cache_key = ':'.join(
-                [force_text(x) for x in args_rewrite(*args)] +
-                [force_text('{}={}'.format(k, v)) for k, v in kwargs.items()]
+            cache_key = ":".join(
+                [force_text(x) for x in args_rewrite(*args)]
+                + [force_text("{}={}".format(k, v)) for k, v in kwargs.items()]
             )
-            return hashlib.md5(force_bytes(
-                'cache_memoize' + (prefix or func.__name__) + cache_key
-            )).hexdigest()
+            return hashlib.md5(
+                force_bytes("cache_memoize" + (prefix or func.__name__) + cache_key)
+            ).hexdigest()
 
         @wraps(func)
         def inner(*args, **kwargs):
@@ -105,7 +106,7 @@ def inner(*args, **kwargs):
                 cache_key = _make_cache_key(*args, **kwargs)
             else:
                 cache_key = key_generator_callable(*args, **kwargs)
-            if kwargs.pop('_refresh', False):
+            if kwargs.pop("_refresh", False):
                 result = MARKER
             else:
                 result = cache.get(cache_key, MARKER)
diff --git a/tests/conftest.py b/tests/conftest.py
index 7e4723b..157f161 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -4,5 +4,6 @@
 @pytest.fixture(autouse=True)
 def clear_cache():
     from django.core.cache import caches
-    caches['default'].clear()
-    caches['locmem'].clear()
+
+    caches["default"].clear()
+    caches["locmem"].clear()
diff --git a/tests/settings.py b/tests/settings.py
index 175bf60..61a1cf9 100644
--- a/tests/settings.py
+++ b/tests/settings.py
@@ -3,9 +3,9 @@
 # Build paths inside the project like this: os.path.join(BASE_DIR, ...)
 BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 
-ROOT_URLCONF = 'tests.urls'
+ROOT_URLCONF = "tests.urls"
 
-SECRET_KEY = 'z$uhu93+ydzttmn6l2ky834&p$78)h*945w-srqjpbs!x!b)hy'
+SECRET_KEY = "z$uhu93+ydzttmn6l2ky834&p$78)h*945w-srqjpbs!x!b)hy"
 
 DEBUG = True
 
@@ -13,56 +13,49 @@
 
 
 INSTALLED_APPS = [
-    'django.contrib.admin',
-    'django.contrib.auth',
-    'django.contrib.contenttypes',
-    'django.contrib.sessions',
-    'django.contrib.messages',
-    'django.contrib.staticfiles',
+    "django.contrib.admin",
+    "django.contrib.auth",
+    "django.contrib.contenttypes",
+    "django.contrib.sessions",
+    "django.contrib.messages",
+    "django.contrib.staticfiles",
 ]
 
 MIDDLEWARE = [
-    'django.middleware.security.SecurityMiddleware',
-    'django.contrib.sessions.middleware.SessionMiddleware',
-    'django.middleware.common.CommonMiddleware',
-    'django.middleware.csrf.CsrfViewMiddleware',
-    'django.contrib.auth.middleware.AuthenticationMiddleware',
-    'django.contrib.messages.middleware.MessageMiddleware',
-    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+    "django.middleware.security.SecurityMiddleware",
+    "django.contrib.sessions.middleware.SessionMiddleware",
+    "django.middleware.common.CommonMiddleware",
+    "django.middleware.csrf.CsrfViewMiddleware",
+    "django.contrib.auth.middleware.AuthenticationMiddleware",
+    "django.contrib.messages.middleware.MessageMiddleware",
+    "django.middleware.clickjacking.XFrameOptionsMiddleware",
 ]
 
 
 TEMPLATES = [
     {
-        'BACKEND': 'django.template.backends.django.DjangoTemplates',
-        'DIRS': [],
-        'APP_DIRS': True,
-        'OPTIONS': {
-            'context_processors': [
-                'django.template.context_processors.debug',
-                'django.template.context_processors.request',
-                'django.contrib.auth.context_processors.auth',
-                'django.contrib.messages.context_processors.messages',
-            ],
+        "BACKEND": "django.template.backends.django.DjangoTemplates",
+        "DIRS": [],
+        "APP_DIRS": True,
+        "OPTIONS": {
+            "context_processors": [
+                "django.template.context_processors.debug",
+                "django.template.context_processors.request",
+                "django.contrib.auth.context_processors.auth",
+                "django.contrib.messages.context_processors.messages",
+            ]
         },
-    },
+    }
 ]
 
 
-DATABASES = {
-    'default': {
-        'ENGINE': 'django.db.backends.sqlite3',
-        'NAME': ':memory:',
-    }
-}
+DATABASES = {"default": {"ENGINE": "django.db.backends.sqlite3", "NAME": ":memory:"}}
 
 
 CACHES = {
-    'default': {
-        'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
-        'LOCATION': '127.0.0.1:11211',
-    },
-    'locmem': {
-        'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
+    "default": {
+        "BACKEND": "django.core.cache.backends.memcached.MemcachedCache",
+        "LOCATION": "127.0.0.1:11211",
     },
+    "locmem": {"BACKEND": "django.core.cache.backends.locmem.LocMemCache"},
 }
diff --git a/tests/test_cache_memoize.py b/tests/test_cache_memoize.py
index 31af572..6de095f 100644
--- a/tests/test_cache_memoize.py
+++ b/tests/test_cache_memoize.py
@@ -8,9 +8,9 @@ def test_cache_memoize():
     calls_made = []
 
     @cache_memoize(10)
-    def runmeonce(a, b, k='bla'):
+    def runmeonce(a, b, k="bla"):
         calls_made.append((a, b, k))
-        return '{} {} {}'.format(a, b, k)  # sample implementation
+        return "{} {} {}".format(a, b, k)  # sample implementation
 
     runmeonce(1, 2)
     runmeonce(1, 2)
@@ -18,37 +18,38 @@ def runmeonce(a, b, k='bla'):
     runmeonce(1, 3)
     assert len(calls_made) == 2
     # should work with most basic types
-    runmeonce(1.1, 'foo')
-    runmeonce(1.1, 'foo')
+    runmeonce(1.1, "foo")
+    runmeonce(1.1, "foo")
     assert len(calls_made) == 3
     # even more "advanced" types
-    runmeonce(1.1, 'foo', k=list('åäö'))
-    runmeonce(1.1, 'foo', k=list('åäö'))
+    runmeonce(1.1, "foo", k=list("åäö"))
+    runmeonce(1.1, "foo", k=list("åäö"))
     assert len(calls_made) == 4
     # And shouldn't be a problem even if the arguments are really long
-    runmeonce('A' * 200, 'B' * 200, {'C' * 100: 'D' * 100})
+    runmeonce("A" * 200, "B" * 200, {"C" * 100: "D" * 100})
     assert len(calls_made) == 5
 
     # different prefixes
-    @cache_memoize(10, prefix='first')
+    @cache_memoize(10, prefix="first")
     def foo(value):
         calls_made.append(value)
-        return 'ho'
+        return "ho"
 
-    @cache_memoize(10, prefix='second')
+    @cache_memoize(10, prefix="second")
     def bar(value):
         calls_made.append(value)
-        return 'ho'
+        return "ho"
 
-    foo('hey')
-    bar('hey')
+    foo("hey")
+    bar("hey")
     assert len(calls_made) == 7
 
     # Test when you don't care about the result
-    @cache_memoize(10, store_result=False, prefix='different')
-    def returnnothing(a, b, k='bla'):
+    @cache_memoize(10, store_result=False, prefix="different")
+    def returnnothing(a, b, k="bla"):
         calls_made.append((a, b, k))
         # note it returns None
+
     returnnothing(1, 2)
     returnnothing(1, 2)
     assert len(calls_made) == 8
@@ -66,11 +67,7 @@ def hit_callable(arg):
     def miss_callable(arg):
         misses.append(arg)
 
-    @cache_memoize(
-        10,
-        hit_callable=hit_callable,
-        miss_callable=miss_callable,
-    )
+    @cache_memoize(10, hit_callable=hit_callable, miss_callable=miss_callable)
     def runmeonce(arg):
         calls_made.append(arg)
         return arg * 2
@@ -192,7 +189,7 @@ def runmeonce(a):
         return a * 2
 
     runmeonce_default = cache_memoize(10)(runmeonce)
-    runmeonce_locmem = cache_memoize(10, cache_alias='locmem')(runmeonce)
+    runmeonce_locmem = cache_memoize(10, cache_alias="locmem")(runmeonce)
 
     runmeonce_default(10)
     assert len(calls_made) == 1
@@ -209,8 +206,8 @@ def test_cache_memoize_works_with_custom_key_generator():
     calls_made = []
 
     def key_generator(*args):
-        key = (':{}' * len(args)).format(*args)
-        return 'custom_namespace:{}'.format(key)
+        key = (":{}" * len(args)).format(*args)
+        return "custom_namespace:{}".format(key)
 
     @cache_memoize(10, key_generator_callable=key_generator)
     def runmeonce(arg1, arg2):
diff --git a/tox.ini b/tox.ini
index ae04b23..5803f43 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,7 +3,7 @@ skipsdist = True
 usedevelop = True
 minversion = 1.8
 envlist =
-    flake8-py36,
+    lint-py36,
     readme-py27,
     docs-py27-dj{18,110},
     py27-django{18,19,110,111},
@@ -39,11 +39,6 @@ commands =
 commands = python setup.py check -r -s
 deps = readme_renderer
 
-[testenv:flake8-py36]
-commands = flake8 src tests
-deps =
-    flake8
-
-[flake8]
-exclude=.tox
-#ignore=E501,E127,E128,E124
+[testenv:lint-py36]
+extras = dev
+commands=therapist run --use-tracked-files