diff --git a/km3buu/__version__.py b/km3buu/__version__.py
index 9667750318d5337d3ce0c369febe8f2a94e1b1dc..5996d319ed7c18627a66a822f2ff6b14cfdd483f 100644
--- a/km3buu/__version__.py
+++ b/km3buu/__version__.py
@@ -13,10 +13,10 @@ from os.path import dirname, realpath, join
 
 from setuptools_scm import get_version
 
-version = 'unknown version'
+version = "unknown version"
 
 try:
-    version = get_version(root='..', relative_to=__file__)
+    version = get_version(root="..", relative_to=__file__)
 except LookupError:
-    with open(join(realpath(dirname(__file__)), "version.txt"), 'r') as fobj:
+    with open(join(realpath(dirname(__file__)), "version.txt"), "r") as fobj:
         version = fobj.read()
diff --git a/km3buu/config.py b/km3buu/config.py
index 8b986dca0ffdd67165cf479e21d1797963ed284d..1991b15793d5cb587a2606b84ae3a9c57146ff3b 100644
--- a/km3buu/config.py
+++ b/km3buu/config.py
@@ -22,7 +22,7 @@ __maintainer__ = "Johannes Schumann"
 __email__ = "jschumann@km3net.de"
 __status__ = "Development"
 
-CONFIG_PATH = os.path.expanduser('~/.km3buu/config')
+CONFIG_PATH = os.path.expanduser("~/.km3buu/config")
 
 log = get_logger(__name__)
 
@@ -37,7 +37,7 @@ class Config(object):
         if section not in self.config.sections():
             self.config.add_section(section)
         self.config.set(section, key, value)
-        with open(self._config_path, 'w') as f:
+        with open(self._config_path, "w") as f:
             self.config.write(f)
 
     def get(self, section, key, default=None):
@@ -59,17 +59,17 @@ class Config(object):
             dev_path = abspath(join(dirname(__file__), os.pardir, IMAGE_NAME))
             if isfile(dev_path):
                 image_path = dev_path
-            elif click.confirm("Is the GiBUU image already available?",
-                               default=False):
-                image_path = click.prompt("GiBUU image path?",
-                                          type=click.Path(exists=True,
-                                                          dir_okay=False))
+            elif click.confirm("Is the GiBUU image already available?", default=False):
+                image_path = click.prompt(
+                    "GiBUU image path?", type=click.Path(exists=True, dir_okay=False)
+                )
             elif click.confirm("Install image from remote?", default=True):
                 default_dir = join(os.environ["HOME"], ".km3buu")
                 image_dir = click.prompt(
                     "GiBUU image path (default: ~/.km3buu) ?",
                     type=click.Path(exists=True, file_okay=False),
-                    default=default_dir)
+                    default=default_dir,
+                )
                 image_path = build_image(image_dir)
             self.set(section, key, image_path)
         return image_path