Method for adding custom music

Monika After Story/game/zz_music_selector.rpy

@@ -213,6 +213,36 @@ init -1 python in songs:
         if chan.mixer in renpy.game.preferences.volumes:
             renpy.game.preferences.volumes[chan.mixer] = _sanitizeVolume(value)
 
+    def addSongEntry(path, display_name, by_user=False):
+        """
+        Adds song entry to selection list. Automatically paginates and cleans
+        title text.
+
+        NOTE: Does not perform loop/metadata prefix scan. Path will be added as-is.
+        NOTE: Checks if the path exists (loop prefix is ignored for this check.)
+
+        IN:
+            path - path to the music file
+            display_name - title of the song to show in music selector
+            by_user (default False) - whether this is an action user has done
+                (sets the corresponding PM variable)
+
+        OUT:
+            True if path exists and song entry was created, False otherwise.
+        """
+
+        filepath = path.split(">")[:-1]
+        if not os.path.exists(filepath):
+            return False
+
+        music_choices.append((cleanGUIText(display_name), path))
+        music_pages = __paginate(music_choices)
+
+        if by_user:
+            store.persistent._mas_pm_added_custom_bgm = True
+
+        return True
+
 
     def _sanitizeVolume(value):
         """