diff --git a/streamrip/bases.py b/streamrip/bases.py
index 2330175..89f3c8a 100644
--- a/streamrip/bases.py
+++ b/streamrip/bases.py
@@ -241,7 +241,7 @@ class Track:
             self.move(self.final_path)
 
         database = kwargs.get("database")
-        if database is not None:
+        if database:
             database.add(self.id)
             logger.debug(f"{self.id} added to database")
 
diff --git a/streamrip/metadata.py b/streamrip/metadata.py
index 993ad49..0a4e2f5 100644
--- a/streamrip/metadata.py
+++ b/streamrip/metadata.py
@@ -63,14 +63,14 @@ class TrackMetadata:
         self.album: str
         self.albumartist: str
         self.composer: str
-        self.comment: Optional[str]
-        self.description: Optional[str]
-        self.purchase_date: Optional[str]
-        self.grouping: Optional[str]
-        self.lyrics: Optional[str]
-        self.encoder: Optional[str]
-        self.compilation: Optional[str]
-        self.cover: str
+        self.comment: Optional[str] = None
+        self.description: Optional[str] = None
+        self.purchase_date: Optional[str] = None
+        self.grouping: Optional[str] = None
+        self.lyrics: Optional[str] = None
+        self.encoder: Optional[str] = None
+        self.compilation: Optional[str] = None
+        self.cover: Optional[str] = None
         self.tracktotal: int
         self.tracknumber: int
         self.discnumber: int
diff --git a/streamrip/tracklists.py b/streamrip/tracklists.py
index 2fe6634..ebcb0b9 100644
--- a/streamrip/tracklists.py
+++ b/streamrip/tracklists.py
@@ -2,6 +2,8 @@
 downloadable form.
 """
 
+from __future__ import annotations
+
 import functools
 import logging
 import os
@@ -561,6 +563,7 @@ class Artist(Tracklist):
         logger.debug(f"Length of tracklist {len(self)}")
         logger.debug(f"Filters: {filters}")
 
+        final: Iterable
         if "repeats" in filters:
             final = self._remove_repeats(bit_depth=max, sampling_rate=min)
             filters = tuple(f for f in filters if f != "repeats")