Misc tidying

app/helpers.py

@@ -404,22 +404,6 @@ def show_warning(parent: Optional[QMainWindow], title: str, msg: str) -> None:
     QMessageBox.warning(parent, title, msg, buttons=QMessageBox.StandardButton.Cancel)
 
 
-def singleton(cls):
-    """
-    Make a class a Singleton class (see
-    https://realpython.com/primer-on-python-decorators/#creating-singletons)
-    """
-
-    @functools.wraps(cls)
-    def wrapper_singleton(*args, **kwargs):
-        if not wrapper_singleton.instance:
-            wrapper_singleton.instance = cls(*args, **kwargs)
-        return wrapper_singleton.instance
-
-    wrapper_singleton.instance = None
-    return wrapper_singleton
-
-
 def trailing_silence(
     audio_segment: AudioSegment,
     silence_threshold: int = -50,

app/models.py

@@ -72,7 +72,9 @@ class NoteColours(dbtables.NoteColoursTable):
         return result
 
     @staticmethod
-    def get_colour(session: Session, text: str, foreground: bool = False) -> Optional[str]:
+    def get_colour(
+        session: Session, text: str, foreground: bool = False
+    ) -> Optional[str]:
         """
         Parse text and return background (foreground if foreground==True) colour
         string if matched, else None
@@ -245,10 +247,7 @@ class Playlists(dbtables.PlaylistsTable):
 
         return session.scalars(
             select(cls)
-            .where(
+            .where(cls.is_template.is_(True), cls.deleted.is_not(True))
-                cls.is_template.is_(True),
-                cls.deleted.is_not(True)
-            )
             .order_by(cls.name)
         ).all()