diff --git a/cozy/ui/main_view.py b/cozy/ui/main_view.py
index 98fa63c7..0a4d7fa0 100644
--- a/cozy/ui/main_view.py
+++ b/cozy/ui/main_view.py
@@ -15,16 +15,14 @@
 from cozy.media.importer import Importer, ScanStatus
 from cozy.media.player import Player
 from cozy.model.settings import Settings as SettingsModel
-
 from cozy.ui.about_window import AboutWindow
 from cozy.ui.book_detail_view import BookDetailView
 from cozy.ui.library_view import LibraryView
 from cozy.ui.preferences_window import PreferencesWindow
 from cozy.ui.widgets.first_import_button import FirstImportButton
-
-from cozy.view_model.storages_view_model import StoragesViewModel
 from cozy.view_model.playback_control_view_model import PlaybackControlViewModel
 from cozy.view_model.playback_speed_view_model import PlaybackSpeedViewModel
+from cozy.view_model.storages_view_model import StoragesViewModel
 
 log = logging.getLogger("ui")
 
@@ -63,7 +61,9 @@ def activate(self, library_view: LibraryView):
         self.check_for_tracks()
 
     def startup(self):
-        self.window_builder = Gtk.Builder.new_from_resource("/com/github/geigi/cozy/ui/main_window.ui")
+        self.window_builder = Gtk.Builder.new_from_resource(
+            "/com/github/geigi/cozy/ui/main_window.ui"
+        )
         self.window: Adw.ApplicationWindow = self.window_builder.get_object("app_window")
 
     def __init_window(self):
@@ -214,7 +214,10 @@ def switch_to_playing(self):
         Switch the UI state back to playing.
         This enables all UI functionality for the user.
         """
-        if self.navigation_view.props.visible_page != "book_overview" and self.main_stack.props.visible_child_name != "welcome":
+        if (
+            self.navigation_view.props.visible_page != "book_overview"
+            and self.main_stack.props.visible_child_name != "welcome"
+        ):
             self.navigation_view.pop_to_tag("main")
 
         if self._player.loaded_book:
@@ -314,4 +317,3 @@ def _save_window_size(self, *_):
         self.application_settings.window_width = width
         self.application_settings.window_height = height
         self.application_settings.window_maximize = self.window.is_maximized()
-
diff --git a/cozy/ui/media_controller.py b/cozy/ui/media_controller.py
index c4f77873..78d1e4ac 100644
--- a/cozy/ui/media_controller.py
+++ b/cozy/ui/media_controller.py
@@ -107,18 +107,33 @@ def _set_cover_image(self, book: Book):
     @inject.param("main_window", "MainWindow")
     def _setup_shortcuts(self, main_window):
         main_window.create_action("play_pause", self._play_clicked, ["space"], only_main_view=True)
-        main_window.create_action("seek_rewind", self._rewind_clicked, ["Left"], only_main_view=True)
-        main_window.create_action("seek_forward", self._forward_clicked, ["Right"], only_main_view=True)
+        main_window.create_action(
+            "seek_rewind", self._rewind_clicked, ["Left"], only_main_view=True
+        )
+        main_window.create_action(
+            "seek_forward", self._forward_clicked, ["Right"], only_main_view=True
+        )
 
         main_window.create_action("volume_up", self._volume_up, ["Up"], only_main_view=True)
         main_window.create_action("volume_down", self._volume_down, ["Down"], only_main_view=True)
 
-        main_window.create_action("speed_up", self._speed_up, ["plus", "KP_Add"], only_main_view=True)
-        main_window.create_action("speed_down", self._speed_down, ['minus',  "KP_Subtract", 'hyphen'], only_main_view=True)
-        main_window.create_action("speed_reset", self._speed_reset, ['equal'], only_main_view=True)
+        main_window.create_action(
+            "speed_up", self._speed_up, ["plus", "KP_Add"], only_main_view=True
+        )
+        main_window.create_action(
+            "speed_down", self._speed_down, ["minus", "KP_Subtract", "hyphen"], only_main_view=True
+        )
+        main_window.create_action("speed_reset", self._speed_reset, ["equal"], only_main_view=True)
 
-        main_window.create_action("previous_chapter", self._previous_chapter, ["Page_Down", "<primary>Left"], only_main_view=True)
-        main_window.create_action("next_chapter", self._next_chapter, ["Page_Up", "<primary>Right"], only_main_view=True)
+        main_window.create_action(
+            "previous_chapter",
+            self._previous_chapter,
+            ["Page_Down", "<primary>Left"],
+            only_main_view=True,
+        )
+        main_window.create_action(
+            "next_chapter", self._next_chapter, ["Page_Up", "<primary>Right"], only_main_view=True
+        )
 
     def _on_book_changed(self) -> None:
         book = self._playback_control_view_model.book
diff --git a/cozy/view_model/playback_speed_view_model.py b/cozy/view_model/playback_speed_view_model.py
index f32d3df4..cc8d4484 100644
--- a/cozy/view_model/playback_speed_view_model.py
+++ b/cozy/view_model/playback_speed_view_model.py
@@ -36,11 +36,11 @@ def _on_player_event(self, event: str, message):
             self._notify("playback_speed")
 
     def speed_up(self):
-        self.playback_speed = min(self.playback_speed + .1, 3.5)
+        self.playback_speed = min(self.playback_speed + 0.1, 3.5)
         self._notify("playback_speed")
 
     def speed_down(self):
-        self.playback_speed = max(self.playback_speed - .1, 0.5)
+        self.playback_speed = max(self.playback_speed - 0.1, 0.5)
         self._notify("playback_speed")
 
     def speed_reset(self):