Fix artists cache initialising (thanks mathieui)

diff --git a/sima/client.py b/sima/client.py
index 926e2952acc5a9c177d8b622f01bb4d620935217..e171c0b1d6c1934d728470e649b06c104e486992 100644 (file)
--- a/sima/client.py
+++ b/sima/client.py
@@ -159,8 +159,8 @@ class PlayerClient(Player):
         else:
             self.log.info('Player: Initialising cache!')
         self._cache = {
-                'artists': None,
-                'nombid_artists': None,
+                'artists': frozenset(),
+                'nombid_artists': frozenset(),
                 }
         self._cache['artists'] = frozenset(self._execute('list', ['artist']))
         if Artist.use_mbid:
@@ -336,7 +336,7 @@ class PlayerClient(Player):
 
     @property
     def artists(self):
-        return self._cache.get('artists') | self._cache.get('nombid_artists')
+        return self._cache.get('artists')
 
     @property
     def state(self):