Fixed lint issues

tests/unit/test_oauth.py

@@ -6,10 +6,9 @@ import unittest
 import six.moves.urllib.parse as urllibparse
 
 from spotipy import SpotifyOAuth, SpotifyPKCE
-from spotipy.cache_handler import CacheHandler
 from spotipy.oauth2 import SpotifyClientCredentials, SpotifyOauthError
 from spotipy.oauth2 import SpotifyStateError
-from spotipy import CacheFileHandler
+from spotipy import MemoryCacheHandler, CacheFileHandler
 
 try:
     import unittest.mock as mock
@@ -233,6 +232,7 @@ class TestSpotifyClientCredentials(unittest.TestCase):
             oauth.get_access_token()
         self.assertEqual(error.exception.error, 'invalid_client')
 
+
 class SpotifyPKCECacheTest(unittest.TestCase):
 
     @patch.multiple(SpotifyPKCE,