diff --git a/.githooks/pre-commit b/.githooks/pre-commit
new file mode 100644
index 0000000000000000000000000000000000000000..3d7459ba2410c663b83fbc9f3e506f748c7468cc
--- /dev/null
+++ b/.githooks/pre-commit
@@ -0,0 +1,76 @@
+#!/bin/sh
+#
+# An example hook script to verify what is about to be committed.
+# Called by "git commit" with no arguments.  The hook should
+# exit with non-zero status after issuing an appropriate message if
+# it wants to stop the commit.
+#
+# To enable this hook, rename this file to "pre-commit".
+
+if git rev-parse --verify HEAD >/dev/null 2>&1
+then
+	against=HEAD
+else
+	# Initial commit: diff against an empty tree object
+	against=$(git hash-object -t tree /dev/null)
+fi
+
+# If you want to allow non-ASCII filenames set this variable to true.
+allownonascii=$(git config --bool hooks.allownonascii)
+
+# Redirect output to stderr.
+exec 1>&2
+
+# Cross platform projects tend to avoid non-ASCII filenames; prevent
+# them from being added to the repository. We exploit the fact that the
+# printable range starts at the space character and ends with tilde.
+if [ "$allownonascii" != "true" ] &&
+	# Note that the use of brackets around a tr range is ok here, (it's
+	# even required, for portability to Solaris 10's /usr/bin/tr), since
+	# the square bracket bytes happen to fall in the designated range.
+	test $(git diff --cached --name-only --diff-filter=A -z $against |
+	  LC_ALL=C tr -d '[ -~]\0' | wc -c) != 0
+then
+	cat <<\EOF
+Error: Attempt to add a non-ASCII file name.
+
+This can cause problems if you want to work with people on other platforms.
+
+To be portable it is advisable to rename the file.
+
+If you know what you are doing you can disable this check using:
+
+  git config hooks.allownonascii true
+EOF
+	exit 1
+fi
+
+# If there are whitespace errors, print the offending file names and fail.
+#exec git diff-index --check --cached $against --
+
+
+
+# NOTE: To activate all hooks in this directory,
+# run "git config --local core.hooksPath .githooks"
+
+# Indicate that hook is running.
+echo "------ BEGIN CUSTOM ${0##*/} HOOK ------"
+
+# Find staged .py files.
+PYFILES=$(
+	git diff --staged --name-only --diff-filter=ACM | 
+	sed -n '/.*\.py/ { s| |\\ |g ; p}'
+)
+
+# Format staged .py files.
+if [ -n "$PYFILES" ]; then
+	if ! black $PYFILES; then
+		exit 1
+	else
+		git add $PYFILES
+	fi
+fi
+
+# Indicate that hook is finished.
+echo "------ END CUSTOM ${0##*/} HOOK ------"
+
diff --git a/examples/overview_complex.py b/examples/overview_complex.py
index 79d5dfeae519f993962ea97aa227bd4934ea7777..16c38d548e17ad13e52b05a31bcb98f104052762 100644
--- a/examples/overview_complex.py
+++ b/examples/overview_complex.py
@@ -10,38 +10,48 @@ import facetswrapper
 
 def load_data():
     """Load UCI census train and test data into dataframes."""
-    features = ["Age", "Workclass", "fnlwgt", "Education", "Education-Num", "Marital Status",
-                "Occupation", "Relationship", "Race", "Sex", "Capital Gain", "Capital Loss",
-                "Hours per week", "Country", "Target"]
+    features = [
+        "Age",
+        "Workclass",
+        "fnlwgt",
+        "Education",
+        "Education-Num",
+        "Marital Status",
+        "Occupation",
+        "Relationship",
+        "Race",
+        "Sex",
+        "Capital Gain",
+        "Capital Loss",
+        "Hours per week",
+        "Country",
+        "Target",
+    ]
     result = pd.read_csv(
         "https://archive.ics.uci.edu/ml/machine-learning-databases/adult/adult.test",
         names=features,
-        sep=r'\s*,\s*',
+        sep=r"\s*,\s*",
         skiprows=[0],
-        engine='python',
-        na_values="?")
+        engine="python",
+        na_values="?",
+    )
     return result
 
 
 def write_overview_html(data, output_filepath):
     """Generate overview html code and write it in a file."""
-    overview_html = facetswrapper.overview.overview_html(data, groupby=["Target", "Sex"])
-    with open(output_filepath, 'w') as file:
+    overview_html = facetswrapper.overview.overview_html(
+        data, groupby=["Target", "Sex"]
+    )
+    with open(output_filepath, "w") as file:
         file.write(overview_html)
 
 
 if __name__ == "__main__":
-    print("Loading data...  ", end='', flush=True)
+    print("Loading data...  ", end="", flush=True)
     data = load_data()
-    print('Done')
-    print('Generating HTML page...  ', end='', flush=True)
-    output_filepath = Path(sys.argv[0]).with_suffix('.html')
+    print("Done")
+    print("Generating HTML page...  ", end="", flush=True)
+    output_filepath = Path(sys.argv[0]).with_suffix(".html")
     write_overview_html(data, output_filepath)
-    print('Done')
-
-
-
-
-
-
-
+    print("Done")
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000000000000000000000000000000000000..a4967d1743f45c172ce9e9f30ede159c4f01e5a5
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,2 @@
+[tool.black]
+exclude =  '/(\.eggs|\.git|\.hg|\.mypy_cache|\.nox|\.tox|\.venv|_build|buck-out|build|dist|venv|src/facets)/'
diff --git a/setup.py b/setup.py
index 9b6c02b01a6a175fdae5cc17adfa01aa198f7140..53cb3d9bd67c00468d3a1ec21c393825c9b96dfd 100644
--- a/setup.py
+++ b/setup.py
@@ -26,10 +26,10 @@ setup(
     license="",
     url="https://gitlab.com/sivan.altinakar/facetswrapper",
     project_urls={
-        'Documentation': 'https://gitlab.com/sivan.altinakar/facetswrapper/blob/master/README.md',
+        "Documentation": "https://gitlab.com/sivan.altinakar/facetswrapper/blob/master/README.md",
         # 'Funding': 'https://donate.pypi.org',
         # 'Say Thanks!': 'http://saythanks.io/to/example',
-        'Source': 'https://gitlab.com/sivan.altinakar/facetswrapper',
+        "Source": "https://gitlab.com/sivan.altinakar/facetswrapper",
         # 'Tracker': 'https://github.com/pypa/sampleproject/issues',
     },
     packages=find_packages("src"),
@@ -39,13 +39,8 @@ setup(
     include_package_data=True,
     zip_safe=False,
     python_requires=">=3.6",
-    install_requires=[
-        'pandas',
-        'protobuf',
-    ],
-    extras_require={  # Optional
-        'test': [],
-    },
+    install_requires=["pandas", "protobuf"],
+    extras_require={"dev": ["black"]},  # Optional
     classifiers=(
         "Development Status :: 4 - Beta",
         "Intended Audience :: Science/Research",
@@ -54,7 +49,7 @@ setup(
         "Programming Language :: Python :: 3",
         "Topic :: Scientific/Engineering :: Visualization",
     ),
-    keywords='dataviz data_visualization wrapper',
+    keywords="dataviz data_visualization wrapper",
 )
 
 
@@ -73,5 +68,3 @@ pip install --no-deps -e .
 python3 setup.py sdist bdist_wheel
 ```
 """
-
-
diff --git a/src/facetswrapper/__init__.py b/src/facetswrapper/__init__.py
index 1c23fd3285b49ed20d8437680d064b592f02a154..13a9ca717f53dccb2b492dcc8e44ed42564394d8 100644
--- a/src/facetswrapper/__init__.py
+++ b/src/facetswrapper/__init__.py
@@ -1 +1 @@
-from .overview import overview_html
\ No newline at end of file
+from .overview import overview_html
diff --git a/src/facetswrapper/overview.py b/src/facetswrapper/overview.py
index 09b8551728c2f27dd5536cf39d6453e86d60a8f5..e193c2d86940627a151273c9320825e48cdb1938 100644
--- a/src/facetswrapper/overview.py
+++ b/src/facetswrapper/overview.py
@@ -10,7 +10,9 @@ import sys
 # from pathlib import Path
 # print(Path.cwd())
 
-from facets.facets_overview.python.generic_feature_statistics_generator import GenericFeatureStatisticsGenerator
+from facets.facets_overview.python.generic_feature_statistics_generator import (
+    GenericFeatureStatisticsGenerator,
+)
 import base64
 
 # import pandas as pandas