diff --git a/appengine/flexible/django_cloudsql/mysite/settings.py b/appengine/flexible/django_cloudsql/mysite/settings.py
index fbb767d978f..f8032204fb6 100644
--- a/appengine/flexible/django_cloudsql/mysite/settings.py
+++ b/appengine/flexible/django_cloudsql/mysite/settings.py
@@ -86,8 +86,9 @@
 # In the flexible environment, you connect to CloudSQL using a unix socket.
 # Locally, you can use the CloudSQL proxy to proxy a localhost connection
 # to the instance
-    DATABASES['default']['HOST'] = '/cloudsql/<your-cloudsql-connection-string>'
+DATABASES['default']['HOST'] = '/cloudsql/<your-cloudsql-connection-string>'
 if os.getenv('GAE_APPENGINE_HOSTNAME'):
+    pass
 else:
     DATABASES['default']['HOST'] = '127.0.0.1'
 # [END dbconfig]
diff --git a/appengine/flexible/django_cloudsql/mysite/urls.py b/appengine/flexible/django_cloudsql/mysite/urls.py
index d2fc27790dd..302e8e9e675 100644
--- a/appengine/flexible/django_cloudsql/mysite/urls.py
+++ b/appengine/flexible/django_cloudsql/mysite/urls.py
@@ -12,10 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from django.conf import settings
 from django.conf.urls import include, url
 from django.contrib import admin
 from django.contrib.staticfiles.urls import staticfiles_urlpatterns
-from django.conf import settings
 
 urlpatterns = [url(r'^', include('polls.urls')),
                url(r'^admin/', admin.site.urls)]
diff --git a/appengine/standard/angular/main.py b/appengine/standard/angular/main.py
index 3380d304a1a..127605e7d21 100644
--- a/appengine/standard/angular/main.py
+++ b/appengine/standard/angular/main.py
@@ -14,10 +14,10 @@
 
 import json
 
-import model
-
 import webapp2
 
+import model
+
 
 def AsDict(guest):
     return {'id': guest.key.id(), 'first': guest.first, 'last': guest.last}
diff --git a/appengine/standard/i18n/main.py b/appengine/standard/i18n/main.py
index e50ab1260a0..e2277049510 100644
--- a/appengine/standard/i18n/main.py
+++ b/appengine/standard/i18n/main.py
@@ -20,10 +20,10 @@
 For more information, see README.md
 """
 
-from i18n_utils import BaseHandler
-
 import webapp2
 
+from i18n_utils import BaseHandler
+
 
 class MainHandler(BaseHandler):
     """A simple handler with internationalized strings.
diff --git a/container_engine/django_tutorial/polls/migrations/0001_initial.py b/container_engine/django_tutorial/polls/migrations/0001_initial.py
index 2ae7f95ca7f..0609ba72f43 100644
--- a/container_engine/django_tutorial/polls/migrations/0001_initial.py
+++ b/container_engine/django_tutorial/polls/migrations/0001_initial.py
@@ -17,7 +17,9 @@ class Migration(migrations.Migration):
         migrations.CreateModel(
             name='Choice',
             fields=[
-                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('id', models.AutoField(
+                    auto_created=True, primary_key=True, serialize=False,
+                    verbose_name='ID')),
                 ('choice_text', models.CharField(max_length=200)),
                 ('votes', models.IntegerField(default=0)),
             ],
@@ -25,14 +27,19 @@ class Migration(migrations.Migration):
         migrations.CreateModel(
             name='Question',
             fields=[
-                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('id', models.AutoField(
+                    auto_created=True, primary_key=True, serialize=False,
+                    verbose_name='ID')),
                 ('question_text', models.CharField(max_length=200)),
-                ('pub_date', models.DateTimeField(verbose_name=b'date published')),
+                ('pub_date', models.DateTimeField(
+                    verbose_name=b'date published')),
             ],
         ),
         migrations.AddField(
             model_name='choice',
             name='question',
-            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='polls.Question'),
+            field=models.ForeignKey(
+                on_delete=django.db.models.deletion.CASCADE,
+                to='polls.Question'),
         ),
     ]
diff --git a/nox.py b/nox.py
index 083fafa8042..664540e5710 100644
--- a/nox.py
+++ b/nox.py
@@ -61,7 +61,7 @@ def list_files(folder, pattern):
                 yield os.path.join(root, filename)
 
 
-def collect_sample_dirs(start_dir, blacklist=set()):
+def collect_sample_dirs(start_dir, blacklist=set(), suffix='_test.py'):
     """Recursively collects a list of dirs that contain tests.
 
     This works by listing the contents of directories and finding
@@ -69,7 +69,7 @@ def collect_sample_dirs(start_dir, blacklist=set()):
     """
     # Collect all the directories that have tests in them.
     for parent, subdirs, files in os.walk(start_dir):
-        if any(f for f in files if f[-8:] == '_test.py'):
+        if any(f for f in files if f.endswith(suffix) and f not in blacklist):
             # Don't recurse further, since py.test will do that.
             del subdirs[:]
             # This dir has tests in it. yield it.
@@ -240,9 +240,14 @@ def session_lint(session):
     """Lints each sample."""
     sample_directories = session.posargs
     if not sample_directories:
-        sample_directories = collect_sample_dirs('.')
-
-    # On travis, on lint changed samples.
+        # The top-level dir isn't a sample dir - only its subdirs.
+        _, subdirs, _ = next(os.walk('.'))
+        sample_directories = (
+            sample_dir for subdir in subdirs if not subdir.startswith('.')
+            for sample_dir in collect_sample_dirs(
+                    subdir, suffix='.py', blacklist='conftest.py'))
+
+    # On travis, only lint changed samples.
     if ON_TRAVIS:
         changed_files = get_changed_files()
         sample_directories = filter_samples(