diff --git a/payment_paypal/indico_payment_paypal/plugin.py b/payment_paypal/indico_payment_paypal/plugin.py
index 52d4ab2..a894fea 100644
--- a/payment_paypal/indico_payment_paypal/plugin.py
+++ b/payment_paypal/indico_payment_paypal/plugin.py
@@ -62,10 +62,9 @@ class PaypalPaymentPlugin(PaymentPluginMixin, IndicoPlugin):
     def adjust_payment_form_data(self, data):
         event = data['event']
         registration = data['registration']
-        data['item_name'] = '{}: registration for {}'.format(
-            str_to_ascii(remove_accents(registration.full_name)),
-            str_to_ascii(remove_accents(event.title))
-        )
+        plain_name = str_to_ascii(remove_accents(registration.full_name))
+        plain_title = str_to_ascii(remove_accents(event.title))
+        data['item_name'] = f'{plain_name}: registration for {plain_title}'
         data['return_url'] = url_for_plugin('payment_paypal.success', registration.locator.uuid, _external=True)
         data['cancel_url'] = url_for_plugin('payment_paypal.cancel', registration.locator.uuid, _external=True)
         data['notify_url'] = url_for_plugin('payment_paypal.notify', registration.locator.uuid, _external=True)
diff --git a/storage_s3/indico_storage_s3/task.py b/storage_s3/indico_storage_s3/task.py
index 6cf5876..d6a6224 100644
--- a/storage_s3/indico_storage_s3/task.py
+++ b/storage_s3/indico_storage_s3/task.py
@@ -38,5 +38,6 @@ def create_bucket():
                 bucket = storage._get_bucket_name(bucket_date)
                 storage._create_bucket(bucket)
         else:
-            raise RuntimeError('Invalid placeholder combination in bucket name template: {}'
-                               .format(storage.bucket_name_template))
+            raise RuntimeError(
+                f'Invalid placeholder combination in bucket name template: {storage.bucket_name_template}'
+            )