diff --git a/hc/api/views.py b/hc/api/views.py
index fed66d6c..d3728e1a 100644
--- a/hc/api/views.py
+++ b/hc/api/views.py
@@ -19,7 +19,6 @@ from hc.api import schemas
 from hc.api.decorators import authorize, authorize_read, cors, validate_json
 from hc.api.models import Check, Notification, Channel
 from hc.lib.badges import check_signature, get_badge_svg
-from hc.lib.jsonschema import ValidationError, validate
 
 
 class BadChannelException(Exception):
diff --git a/hc/front/admin.py b/hc/front/admin.py
index 8c38f3f3..ad8af2ef 100644
--- a/hc/front/admin.py
+++ b/hc/front/admin.py
@@ -1,3 +1 @@
-from django.contrib import admin
-
-# Register your models here.
+# The front app has no models.
diff --git a/hc/front/models.py b/hc/front/models.py
index 71a83623..ad8af2ef 100644
--- a/hc/front/models.py
+++ b/hc/front/models.py
@@ -1,3 +1 @@
-from django.db import models
-
-# Create your models here.
+# The front app has no models.
diff --git a/hc/front/tests/test_copy.py b/hc/front/tests/test_copy.py
index da8ff8d8..1b91bd1d 100644
--- a/hc/front/tests/test_copy.py
+++ b/hc/front/tests/test_copy.py
@@ -1,4 +1,4 @@
-from hc.api.models import Channel, Check
+from hc.api.models import Check
 from hc.test import BaseTestCase
 
 
diff --git a/hc/front/views.py b/hc/front/views.py
index 20e21308..dac50101 100644
--- a/hc/front/views.py
+++ b/hc/front/views.py
@@ -291,7 +291,6 @@ def serve_doc(request, doc="introduction"):
 
     ctx = {
         "page": "docs",
-        "section": "home",
         "section": doc,
         "content": content,
         "first_line": content.split("\n")[0],
diff --git a/hc/payments/models.py b/hc/payments/models.py
index e7713b80..50aa19c4 100644
--- a/hc/payments/models.py
+++ b/hc/payments/models.py
@@ -1,7 +1,6 @@
 from django.conf import settings
 from django.contrib.auth.models import User
 from django.db import models
-from django.template.loader import render_to_string
 
 if settings.USE_PAYMENTS:
     import braintree