diff --git a/app/commands.py b/app/commands.py
index 6f92aab..8359a7a 100644
--- a/app/commands.py
+++ b/app/commands.py
@@ -6,7 +6,7 @@
 def list_routes():
     """List URLs of all application routes."""
     for rule in sorted(current_app.url_map.iter_rules(), key=lambda r: r.rule):
-        print("{:10} {}".format(", ".join(rule.methods - set(["OPTIONS", "HEAD"])), rule.rule))
+        print("{:10} {}".format(", ".join(rule.methods - {"OPTIONS", "HEAD"}), rule.rule))
 
 
 def setup_commands(application):
diff --git a/app/config.py b/app/config.py
index bdc0574..6e36a6f 100644
--- a/app/config.py
+++ b/app/config.py
@@ -3,12 +3,12 @@
 from kombu import Exchange, Queue
 
 
-class QueueNames(object):
+class QueueNames:
     LETTERS = "letter-tasks"
     ANTIVIRUS = "antivirus-tasks"
 
 
-class Config(object):
+class Config:
     STATSD_ENABLED = True
     STATSD_HOST = os.getenv("STATSD_HOST")
     STATSD_PORT = 8125