diff --git a/development/actual_donwload.py b/development/actual_donwload.py
index 2c9a174..c821734 100644
--- a/development/actual_donwload.py
+++ b/development/actual_donwload.py
@@ -6,8 +6,8 @@ logging.getLogger().setLevel(logging.DEBUG)
 
 if __name__ == "__main__":
     commands = [
-        "s: #a Crystal F",
-        "d: 20"
+        "s: #a Psychonaut 4",
+        "d: 0"
     ]
 
     
diff --git a/music_kraken/objects/source.py b/music_kraken/objects/source.py
index b7e483a..ff68d6a 100644
--- a/music_kraken/objects/source.py
+++ b/music_kraken/objects/source.py
@@ -122,6 +122,9 @@ class SourceCollection:
             yield from self._page_to_source_list[page]
 
     def append(self, source: Source):
+        if source is None:
+            return
+
         existing_source = None
         for key in source.indexing_values:
             if key in self._indexed_sources: