diff --git a/src/migrations/0021_migrate_to_bullseye.py b/src/migrations/0021_migrate_to_bullseye.py
index 38454542b..72dab1c4d 100644
--- a/src/migrations/0021_migrate_to_bullseye.py
+++ b/src/migrations/0021_migrate_to_bullseye.py
@@ -302,18 +302,22 @@ class MyMigration(Migration):
         if " bullseye " not in read_file("/etc/apt/sources.list"):
             tools_update(target="system")
             upgradable_system_packages = list(_list_upgradable_apt_packages())
-            upgradable_system_packages = [package["name"] for package in upgradable_system_packages]
+            upgradable_system_packages = [
+                package["name"] for package in upgradable_system_packages
+            ]
             upgradable_system_packages = set(upgradable_system_packages)
             # Lime2 have hold packages to avoid ethernet instability
             # See https://github.com/YunoHost/arm-images/commit/b4ef8c99554fd1a122a306db7abacc4e2f2942df
-            lime2_hold_packages = set([
-                "armbian-firmware", 
-                "armbian-bsp-cli-lime2", 
-                "linux-dtb-current-sunxi", 
-                "linux-image-current-sunxi", 
-                "linux-u-boot-lime2-current", 
-                "linux-image-next-sunxi"
-            ])
+            lime2_hold_packages = set(
+                [
+                    "armbian-firmware",
+                    "armbian-bsp-cli-lime2",
+                    "linux-dtb-current-sunxi",
+                    "linux-image-current-sunxi",
+                    "linux-u-boot-lime2-current",
+                    "linux-image-next-sunxi",
+                ]
+            )
             if upgradable_system_packages - lime2_hold_packages:
                 raise YunohostError("migration_0021_system_not_fully_up_to_date")