diff --git a/tests/integration/test_aiohttp.py b/tests/integration/test_aiohttp.py
index db28f20..7544081 100644
--- a/tests/integration/test_aiohttp.py
+++ b/tests/integration/test_aiohttp.py
@@ -364,7 +364,7 @@ def test_cookies(scheme, tmpdir):
 def test_cookies_redirect(scheme, tmpdir):
     async def run(loop):
         # Sets cookie as provided by the query string and redirects
-        cookies_url = scheme + '://httpbin.org/cookies/set?Cookie_1=Val_1'
+        cookies_url = scheme + "://httpbin.org/cookies/set?Cookie_1=Val_1"
         tmp = str(tmpdir.join("cookies.yaml"))
 
         # ------------------------- Record -------------------------- #
@@ -373,29 +373,29 @@ def test_cookies_redirect(scheme, tmpdir):
                 cookies_resp = await session.get(cookies_url)
                 assert not cookies_resp.cookies
                 cookies = session.cookie_jar.filter_cookies(cookies_url)
-                assert cookies['Cookie_1'].value == 'Val_1'
+                assert cookies["Cookie_1"].value == "Val_1"
                 assert cassette.play_count == 0
-            cassette.requests[1].headers['Cookie'] == 'Cookie_1=Val_1'
+            cassette.requests[1].headers["Cookie"] == "Cookie_1=Val_1"
 
         # -------------------------- Play --------------------------- #
-        with vcr.use_cassette(tmp, record_mode='none') as cassette:
+        with vcr.use_cassette(tmp, record_mode="none") as cassette:
             async with aiohttp.ClientSession(loop=loop) as session:
                 cookies_resp = await session.get(cookies_url)
                 assert not cookies_resp.cookies
                 cookies = session.cookie_jar.filter_cookies(cookies_url)
-                assert cookies['Cookie_1'].value == 'Val_1'
+                assert cookies["Cookie_1"].value == "Val_1"
                 assert cassette.play_count == 2
-            cassette.requests[1].headers['Cookie'] == 'Cookie_1=Val_1'
+            cassette.requests[1].headers["Cookie"] == "Cookie_1=Val_1"
 
         # Assert that it's ignoring expiration date
-        with vcr.use_cassette(tmp, record_mode='none') as cassette:
-            cassette.responses[0]['headers']['set-cookie'] = [
-                'Cookie_1=Val_1; Expires=Wed, 21 Oct 2015 07:28:00 GMT'
+        with vcr.use_cassette(tmp, record_mode="none") as cassette:
+            cassette.responses[0]["headers"]["set-cookie"] = [
+                "Cookie_1=Val_1; Expires=Wed, 21 Oct 2015 07:28:00 GMT"
             ]
             async with aiohttp.ClientSession(loop=loop) as session:
                 cookies_resp = await session.get(cookies_url)
                 assert not cookies_resp.cookies
                 cookies = session.cookie_jar.filter_cookies(cookies_url)
-                assert cookies['Cookie_1'].value == 'Val_1'
+                assert cookies["Cookie_1"].value == "Val_1"
 
     run_in_loop(run)
diff --git a/vcr/stubs/aiohttp_stubs.py b/vcr/stubs/aiohttp_stubs.py
index 6614cc4..1c1dab5 100644
--- a/vcr/stubs/aiohttp_stubs.py
+++ b/vcr/stubs/aiohttp_stubs.py
@@ -77,11 +77,11 @@ def build_response(vcr_request, vcr_response, history):
         try:
             cookies = SimpleCookie(hdr)
             for cookie_name, cookie in cookies.items():
-                expires = cookie.get('expires', '').strip()
+                expires = cookie.get("expires", "").strip()
                 if expires:
-                    log.debug("Ignoring expiration date: %s=\"%s\"", cookie_name, expires)
-                cookie['expires'] = ''
-                response.cookies.load(cookie.output(header='').strip())
+                    log.debug('Ignoring expiration date: %s="%s"', cookie_name, expires)
+                cookie["expires"] = ""
+                response.cookies.load(cookie.output(header="").strip())
         except CookieError as exc:
             log.warning("Can not load response cookies: %s", exc)