diff --git a/flask_pymemcache.py b/flask_pymemcache.py
index 0fd18bb..7dd8497 100644
--- a/flask_pymemcache.py
+++ b/flask_pymemcache.py
@@ -54,6 +54,7 @@
     memcache.client.set('foo', 'bar')
 
 """
+
 from __future__ import absolute_import, division, print_function
 import flask
 import pymemcache.client
@@ -61,7 +62,6 @@
 
 
 class FlaskPyMemcache(object):
-
     def __init__(self, app=None, conf_key=None):
         """
         :type app: flask.Flask
@@ -76,26 +76,29 @@ def init_app(self, app, conf_key=None):
         :type app: flask.Flask
         :parm str conf_key: Key of flask config.
         """
-        conf_key = conf_key or self.conf_key or 'PYMEMCACHE'
+        conf_key = conf_key or self.conf_key or "PYMEMCACHE"
         self.conf_key = conf_key
         conf = app.config[conf_key]
         if not isinstance(conf, dict):
             raise TypeError("Flask-PyMemcache conf should be dict")
 
-        close_on_teardown = conf.pop('close_on_teardown', False)
+        close_on_teardown = conf.pop("close_on_teardown", False)
 
-        if isinstance(conf['server'], list):
-            conf['servers'] = conf.pop('server')
+        if isinstance(conf["server"], list):
+            conf["servers"] = conf.pop("server")
             client = pymemcache.client.hash.HashClient(**conf)
-        elif isinstance(conf['server'], tuple):
+        elif isinstance(conf["server"], tuple):
             client = pymemcache.client.Client(**conf)
         else:
-            raise TypeError("Flask-PyMemcache conf['server'] should be tuple or list of tuples")
+            raise TypeError(
+                "Flask-PyMemcache conf['server'] should be tuple or list of tuples"
+            )
 
-        app.extensions.setdefault('pymemcache', {})
-        app.extensions['pymemcache'][self] = client
+        app.extensions.setdefault("pymemcache", {})
+        app.extensions["pymemcache"][self] = client
 
         if close_on_teardown:
+
             @app.teardown_appcontext
             def close_connection(exc=None):
                 client.close()
@@ -105,4 +108,4 @@ def client(self):
         """
         :rtype: pymemcache.client.Client
         """
-        return flask.current_app.extensions['pymemcache'][self]
+        return flask.current_app.extensions["pymemcache"][self]
diff --git a/test_flask_pymemcache.py b/test_flask_pymemcache.py
index 0d0d63b..9871409 100644
--- a/test_flask_pymemcache.py
+++ b/test_flask_pymemcache.py
@@ -9,19 +9,20 @@
 
 class TestFlaskPyMemcache(TestCase):
     def test_simple(self):
-        pymc = pymemcache.client.Client(('localhost', 11211))
+        pymc = pymemcache.client.Client(("localhost", 11211))
         memcache = flask_pymemcache.FlaskPyMemcache()
         app = flask.Flask(__name__)
-        app.config['PYMEMCACHE'] = {
-            'server': ('localhost', 11211),
-            'key_prefix': b'px',
-            'close_on_teardown': False}
+        app.config["PYMEMCACHE"] = {
+            "server": ("localhost", 11211),
+            "key_prefix": b"px",
+            "close_on_teardown": False,
+        }
         memcache.init_app(app)
 
         with app.app_context():
-            memcache.client.set(b'foo', b'bar')
+            memcache.client.set(b"foo", b"bar")
 
         with app.app_context():
-            assert memcache.client.get(b'foo') == b'bar'
+            assert memcache.client.get(b"foo") == b"bar"
 
-        assert pymc.get(b'pxfoo') == b'bar'
+        assert pymc.get(b"pxfoo") == b"bar"