diff --git a/repo2docker/app.py b/repo2docker/app.py
index 63643da23..c7f3ab819 100755
--- a/repo2docker/app.py
+++ b/repo2docker/app.py
@@ -7,6 +7,7 @@
 
     python -m repo2docker https://github.com/you/your-repo
 """
+
 import getpass
 import json
 import logging
diff --git a/repo2docker/buildpacks/_r_base.py b/repo2docker/buildpacks/_r_base.py
index 8c87f63f9..de2b7fcb2 100644
--- a/repo2docker/buildpacks/_r_base.py
+++ b/repo2docker/buildpacks/_r_base.py
@@ -3,6 +3,7 @@
 
 Keeping this in r.py would lead to cyclic imports.
 """
+
 from ..semver import parse_version as V
 
 
diff --git a/repo2docker/buildpacks/conda/__init__.py b/repo2docker/buildpacks/conda/__init__.py
index aed5de6f6..2a3e694df 100644
--- a/repo2docker/buildpacks/conda/__init__.py
+++ b/repo2docker/buildpacks/conda/__init__.py
@@ -1,4 +1,5 @@
 """BuildPack for conda environments"""
+
 import os
 import re
 import warnings
@@ -193,15 +194,15 @@ def get_build_script_files(self):
                 raise ValueError(
                     f"Python version {py_version} on {conda_platform} is not supported!"
                 )
-            files[
-                f"conda/{lockfile_name}"
-            ] = self._kernel_environment_file = "/tmp/env/kernel-environment.lock"
+            files[f"conda/{lockfile_name}"] = self._kernel_environment_file = (
+                "/tmp/env/kernel-environment.lock"
+            )
 
             requirements_file_name = f"requirements.py-{py_version}.pip"
             if os.path.exists(os.path.join(HERE, requirements_file_name)):
-                files[
-                    f"conda/{requirements_file_name}"
-                ] = self._kernel_requirements_file = "/tmp/env/kernel-requirements.txt"
+                files[f"conda/{requirements_file_name}"] = (
+                    self._kernel_requirements_file
+                ) = "/tmp/env/kernel-requirements.txt"
         else:
             # server and kernel are the same
             server_py_version = py_version
@@ -216,15 +217,15 @@ def get_build_script_files(self):
                 f"Python version {server_py_version} on {conda_platform} is not supported!"
             )
 
-        files[
-            "conda/" + conda_frozen_name
-        ] = self._nb_environment_file = "/tmp/env/environment.lock"
+        files["conda/" + conda_frozen_name] = self._nb_environment_file = (
+            "/tmp/env/environment.lock"
+        )
 
         # add requirements.txt, if present
         if os.path.exists(os.path.join(HERE, pip_frozen_name)):
-            files[
-                "conda/" + pip_frozen_name
-            ] = self._nb_requirements_file = "/tmp/env/requirements.txt"
+            files["conda/" + pip_frozen_name] = self._nb_requirements_file = (
+                "/tmp/env/requirements.txt"
+            )
 
         files.update(super().get_build_script_files())
         return files
diff --git a/repo2docker/buildpacks/docker.py b/repo2docker/buildpacks/docker.py
index d1dfe4926..9185307ad 100644
--- a/repo2docker/buildpacks/docker.py
+++ b/repo2docker/buildpacks/docker.py
@@ -1,5 +1,6 @@
 """Generates a variety of Dockerfiles based on an input matrix
 """
+
 import os
 
 import docker
diff --git a/repo2docker/buildpacks/julia/julia_project.py b/repo2docker/buildpacks/julia/julia_project.py
index 7b6771c28..0985a33e6 100644
--- a/repo2docker/buildpacks/julia/julia_project.py
+++ b/repo2docker/buildpacks/julia/julia_project.py
@@ -1,4 +1,5 @@
 """Generates a Dockerfile based on an input matrix for Julia"""
+
 import functools
 import os
 from functools import lru_cache
diff --git a/repo2docker/buildpacks/julia/julia_require.py b/repo2docker/buildpacks/julia/julia_require.py
index ab41ffc26..cfea13440 100644
--- a/repo2docker/buildpacks/julia/julia_require.py
+++ b/repo2docker/buildpacks/julia/julia_require.py
@@ -175,7 +175,7 @@ def get_assemble_scripts(self):
                 r"""
             julia /tmp/install-repo-dependencies.jl "%(require)s"
             """
-                % {"require": require}
+                % {"require": require},
                 # TODO: For some reason, `rm`ing the file fails with permission denied.
                 # && rm /tmp/install-repo-dependencies.jl
             )
diff --git a/repo2docker/buildpacks/legacy/__init__.py b/repo2docker/buildpacks/legacy/__init__.py
index 31980f9f7..36bdb8f28 100644
--- a/repo2docker/buildpacks/legacy/__init__.py
+++ b/repo2docker/buildpacks/legacy/__init__.py
@@ -7,6 +7,7 @@
 
 Note: This buildpack has been deprecated.
 """
+
 import logging
 
 
diff --git a/repo2docker/buildpacks/nix/__init__.py b/repo2docker/buildpacks/nix/__init__.py
index 94fd7b7c5..7da3be603 100644
--- a/repo2docker/buildpacks/nix/__init__.py
+++ b/repo2docker/buildpacks/nix/__init__.py
@@ -1,4 +1,5 @@
 """BuildPack for nixpkgs environments"""
+
 import os
 from functools import lru_cache
 
diff --git a/repo2docker/buildpacks/pipfile/__init__.py b/repo2docker/buildpacks/pipfile/__init__.py
index 4b86eed1a..cb6d1ef2b 100644
--- a/repo2docker/buildpacks/pipfile/__init__.py
+++ b/repo2docker/buildpacks/pipfile/__init__.py
@@ -173,9 +173,11 @@ def get_assemble_scripts(self):
                         pipenv --clear \\
                 )""".format(
                     working_directory=working_directory,
-                    install_option="--ignore-pipfile"
-                    if os.path.exists(pipfile_lock)
-                    else "--skip-lock",
+                    install_option=(
+                        "--ignore-pipfile"
+                        if os.path.exists(pipfile_lock)
+                        else "--skip-lock"
+                    ),
                 ),
             )
         )
diff --git a/repo2docker/buildpacks/python/__init__.py b/repo2docker/buildpacks/python/__init__.py
index 188e8e9cf..36740795a 100644
--- a/repo2docker/buildpacks/python/__init__.py
+++ b/repo2docker/buildpacks/python/__init__.py
@@ -1,4 +1,5 @@
 """Generates Dockerfiles based on an input matrix based on Python."""
+
 import os
 from functools import lru_cache
 
diff --git a/repo2docker/contentproviders/base.py b/repo2docker/contentproviders/base.py
index 672c39733..45baf272d 100644
--- a/repo2docker/contentproviders/base.py
+++ b/repo2docker/contentproviders/base.py
@@ -4,6 +4,7 @@
 ContentProviders accept a `spec` of various kinds, and
 provide the contents from the spec to a given output directory.
 """
+
 import logging
 import os
 
diff --git a/repo2docker/semver.py b/repo2docker/semver.py
index d0a2a5b86..97650fa66 100644
--- a/repo2docker/semver.py
+++ b/repo2docker/semver.py
@@ -10,7 +10,6 @@
 constraints.
 """
 
-
 import re
 from functools import lru_cache
 
diff --git a/tests/unit/test_args.py b/tests/unit/test_args.py
index 53913d944..d3e304f00 100644
--- a/tests/unit/test_args.py
+++ b/tests/unit/test_args.py
@@ -1,6 +1,7 @@
 """
 Test argument parsing and r2d construction
 """
+
 import os
 
 import pytest
diff --git a/tests/unit/test_clone_depth.py b/tests/unit/test_clone_depth.py
index 55102eac1..933a18ff8 100644
--- a/tests/unit/test_clone_depth.py
+++ b/tests/unit/test_clone_depth.py
@@ -6,6 +6,7 @@
 and that is the only thing that is tested.
 
 """
+
 import os
 import subprocess
 from tempfile import TemporaryDirectory
diff --git a/tests/unit/test_connect_url.py b/tests/unit/test_connect_url.py
index dbc0c2608..dc72c181b 100644
--- a/tests/unit/test_connect_url.py
+++ b/tests/unit/test_connect_url.py
@@ -1,6 +1,7 @@
 """
 Test if the explict hostname is supplied correctly to the container
 """
+
 import time
 
 import requests
diff --git a/tests/unit/test_env.py b/tests/unit/test_env.py
index fde4aed43..01dd5c724 100644
--- a/tests/unit/test_env.py
+++ b/tests/unit/test_env.py
@@ -1,6 +1,7 @@
 """
 Test that environment variables may be defined
 """
+
 import os
 import subprocess
 import sys
diff --git a/tests/unit/test_external_scripts.py b/tests/unit/test_external_scripts.py
index 278707c87..f33b326f8 100644
--- a/tests/unit/test_external_scripts.py
+++ b/tests/unit/test_external_scripts.py
@@ -1,4 +1,5 @@
 """Test if assemble scripts from outside of r2d repo are accepted."""
+
 import time
 
 from repo2docker.app import Repo2Docker
diff --git a/tests/unit/test_labels.py b/tests/unit/test_labels.py
index e6e1f2e9e..c6d3a7e28 100644
--- a/tests/unit/test_labels.py
+++ b/tests/unit/test_labels.py
@@ -1,6 +1,7 @@
 """
 Test if labels are supplied correctly to the container
 """
+
 from unittest.mock import Mock
 
 import pytest
diff --git a/tests/unit/test_subdir.py b/tests/unit/test_subdir.py
index 4e7007311..5a4e7a38b 100644
--- a/tests/unit/test_subdir.py
+++ b/tests/unit/test_subdir.py
@@ -1,6 +1,7 @@
 """
 Test if the subdirectory is correctly navigated to
 """
+
 import os
 
 import escapism
diff --git a/tests/unit/test_users.py b/tests/unit/test_users.py
index 642e4f3b2..89bee96f9 100644
--- a/tests/unit/test_users.py
+++ b/tests/unit/test_users.py
@@ -1,6 +1,7 @@
 """
 Test that User name and ID mapping works
 """
+
 import os
 import subprocess
 import tempfile
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index c518bbd23..6ce9c2546 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -1,6 +1,7 @@
 """
 Tests for repo2docker/utils.py
 """
+
 import os
 import platform
 import subprocess