diff --git a/tos/models.py b/tos/models.py
index c275f68..db5cf0d 100644
--- a/tos/models.py
+++ b/tos/models.py
@@ -47,7 +47,7 @@ class TermsOfService(BaseModel):
         active = 'inactive'
         if self.active:
             active = 'active'
-        return '{0}: {1}'.format(self.created, active)
+        return f'{self.created}: {active}'
 
     def save(self, *args, **kwargs):
         """ Ensure we're being saved properly """
@@ -72,10 +72,7 @@ class UserAgreement(BaseModel):
     user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='user_agreement', on_delete=models.CASCADE)
 
     def __str__(self):
-        return '%s agreed to TOS: %s' % (
-            self.user.username,
-            self.terms_of_service,
-        )
+        return f'{self.user.username} agreed to TOS: {self.terms_of_service}'
 
 
 def has_user_agreed_latest_tos(user):
diff --git a/tos/tests/test_middleware.py b/tos/tests/test_middleware.py
index bb64376..bacbd2e 100644
--- a/tos/tests/test_middleware.py
+++ b/tos/tests/test_middleware.py
@@ -157,7 +157,7 @@ class BumpCoverage(TestCase):
 
         key_version = cache.get('django:tos:key_version')
 
-        cache.set('django:tos:skip_tos_check:{0}'.format(str(self.user1.id)), True, version=key_version)
+        cache.set(f'django:tos:skip_tos_check:{self.user1.id}', True, version=key_version)
 
         self.client.login(username='user1', password='user1pass')
         response = self.client.get(reverse('index'))
diff --git a/tos/views.py b/tos/views.py
index e5961fc..bba44ab 100644
--- a/tos/views.py
+++ b/tos/views.py
@@ -64,7 +64,7 @@ def check_tos(request, template_name='tos/tos_check.html',
             UserAgreement.objects.get_or_create(terms_of_service=tos, user=user)
 
             key_version = cache.get('django:tos:key_version')
-            cache.delete('django:tos:agreed:{0}'.format(user.pk), version=key_version)
+            cache.delete(f'django:tos:agreed:{user.pk}', version=key_version)
 
             # Log the user in
             auth_login(request, user)