Update app.py

app.py

@@ -295,7 +295,7 @@ def run_exploration(selected_tracks_uris, selected_tracks_genres, playlist_lengt
                             reco = sp.recommendations(seed_tracks=[seed_songs[counter_seed]], market="from_token")['tracks']
                 assert len(reco) > 0
                 for r in reco:
-                    if r['uri'] not in all_tracks_uris:
+                    if r['uri'] not in all_tracks_uris and r['uri'] not in new_songs:
                         new_songs.append(r['uri'])
                         break
             except: