try list instead of tuple?

gazetteer/places/admin.py

@@ -19,15 +19,13 @@ class FeatureTypeFilter(SimpleListFilter):
         human-readable name for the option that will appear
         in the right sidebar.
         """
-        fts = tuple()
+        fts = []
         for ft in FeatureType.objects.all():
             if ft.feature_set.count() > 0:
                 t = (ft.id, ft.__unicode__(),)
                 fts.append(t)
         
-        return (
-            fts,
-        )
+        return fts
 
     def queryset(self, request, queryset):
         """