diff --git a/vdirsyncer/cli.py b/vdirsyncer/cli.py
index 367389e..0a2df18 100644
--- a/vdirsyncer/cli.py
+++ b/vdirsyncer/cli.py
@@ -146,7 +146,7 @@ def _main(env, file_cfg):
                 sys.exit(1)
             a = storage_instance_from_config(all_storages[a])
             b = storage_instance_from_config(all_storages[b])
-            
+
             def x(a=a, b=b, pair_name=pair_name):
                 cli_logger.debug('Syncing {}'.format(pair_name))
                 status = load_status(general['status_path'], pair_name)
diff --git a/vdirsyncer/storage/base.py b/vdirsyncer/storage/base.py
index 0bc4a7e..75f5ac1 100644
--- a/vdirsyncer/storage/base.py
+++ b/vdirsyncer/storage/base.py
@@ -31,7 +31,8 @@ class Storage(object):
     Terminology:
       - UID: Global identifier of the item, across storages.
       - HREF: Per-storage identifier of item, might be UID.
-      - ETAG: Checksum of item, or something similar that changes when the object does
+      - ETAG: Checksum of item, or something similar that changes when the
+              object does.
     '''
     fileext = '.txt'
     _repr_attributes = set()
diff --git a/vdirsyncer/storage/dav/caldav.py b/vdirsyncer/storage/dav/caldav.py
index 42d2af3..567e9b3 100644
--- a/vdirsyncer/storage/dav/caldav.py
+++ b/vdirsyncer/storage/dav/caldav.py
@@ -39,7 +39,8 @@ class CaldavStorage(Storage):
         :param start_date: Start date of timerange to show, default -inf.
         :param end_date: End date of timerange to show, default +inf.
         :param verify: Verify SSL certificate, default True.
-        :param auth: Authentication method, from {'basic', 'digest'}, default 'basic'.
+        :param auth: Authentication method, from {'basic', 'digest'}, default
+            'basic'.
         :param useragent: Default 'vdirsyncer'.
         :param _request_func: Function to use for network calls. Same API as
                               requests.request. Useful for tests.
@@ -80,7 +81,7 @@ class CaldavStorage(Storage):
             headers=headers
         )
         response.raise_for_status()
-        if 'DAV' not in response.headers or 'calendar-access' not in response.headers['DAV']:
+        if 'calendar-access' not in response.headers.get('DAV', ''):
             raise exceptions.StorageError('URL is not a CalDAV collection')
 
     def _default_headers(self):
@@ -101,7 +102,8 @@ class CaldavStorage(Storage):
             self._session = requests.session()
         assert '/' not in item
         url = self.url + item
-        return self._session.request(method, url, data=data, headers=headers, **self._settings)
+        return self._session.request(method, url, data=data, headers=headers,
+                                     **self._settings)
 
     @staticmethod
     def _check_response(response):
@@ -184,8 +186,8 @@ class CaldavStorage(Storage):
                 .find('{urn:ietf:params:xml:ns:caldav}calendar-data').text
             etag = element \
                 .find('{DAV:}propstat') \
-                    .find('{DAV:}prop') \
-                    .find('{DAV:}getetag').text
+                .find('{DAV:}prop') \
+                .find('{DAV:}getetag').text
             if isinstance(obj, bytes):
                 obj = obj.decode(response.encoding)
             if isinstance(etag, bytes):
diff --git a/vdirsyncer/storage/filesystem.py b/vdirsyncer/storage/filesystem.py
index 3914359..e1cfbc2 100644
--- a/vdirsyncer/storage/filesystem.py
+++ b/vdirsyncer/storage/filesystem.py
@@ -45,7 +45,8 @@ class FilesystemStorage(Storage):
     def get(self, href):
         fpath = self._get_filepath(href)
         with open(fpath, 'rb') as f:
-            return Item(f.read().decode(self.encoding)), os.path.getmtime(fpath)
+            return (Item(f.read().decode(self.encoding)),
+                    os.path.getmtime(fpath))
 
     def has(self, href):
         return os.path.isfile(self._get_filepath(href))
diff --git a/vdirsyncer/storage/memory.py b/vdirsyncer/storage/memory.py
index 23c0882..1b8b96b 100644
--- a/vdirsyncer/storage/memory.py
+++ b/vdirsyncer/storage/memory.py
@@ -8,7 +8,7 @@
 '''
 
 import datetime
-from vdirsyncer.storage.base import Item, Storage
+from vdirsyncer.storage.base import Storage
 import vdirsyncer.exceptions as exceptions
 
 
diff --git a/vdirsyncer/tests/storage/__init__.py b/vdirsyncer/tests/storage/__init__.py
index e892981..4fc3969 100644
--- a/vdirsyncer/tests/storage/__init__.py
+++ b/vdirsyncer/tests/storage/__init__.py
@@ -8,14 +8,7 @@
 '''
 __version__ = '0.1.0'
 
-from unittest import TestCase
-import os
-import tempfile
-import shutil
 from vdirsyncer.storage.base import Item
-from vdirsyncer.storage.filesystem import FilesystemStorage
-from vdirsyncer.storage.memory import MemoryStorage
-from vdirsyncer.storage.caldav import CaldavStorage
 import vdirsyncer.exceptions as exceptions
 
 
diff --git a/vdirsyncer/utils.py b/vdirsyncer/utils.py
index 7f48a8e..7822d52 100644
--- a/vdirsyncer/utils.py
+++ b/vdirsyncer/utils.py
@@ -9,6 +9,7 @@
 
 import os
 
+
 def expand_path(p):
     p = os.path.expanduser(p)
     p = os.path.abspath(p)