diff --git a/mopidy_json_client/messages.py b/mopidy_json_client/messages.py
index 01249b3..b73225d 100755
--- a/mopidy_json_client/messages.py
+++ b/mopidy_json_client/messages.py
@@ -151,7 +151,7 @@ def format_app_error(input_error):
 
         output['title'] = input_error.get('message')
         inner_data = input_error.get('data')
-        if isinstance(inner_data, basestring):
+        if isinstance(inner_data, str):
             output['error'] = inner_data
         elif 'message' in input_error:
             output['error'] = inner_data.get('message')
diff --git a/mopidy_json_client/methods_2_0/tracklist.py b/mopidy_json_client/methods_2_0/tracklist.py
index 26737f0..7f5837b 100644
--- a/mopidy_json_client/methods_2_0/tracklist.py
+++ b/mopidy_json_client/methods_2_0/tracklist.py
@@ -109,7 +109,7 @@ def add(self, tracks=None, at_position=None, uri=None, uris=None, **options):
         .. deprecated:: 1.0
             The ``tracks`` and ``uri`` arguments. Use ``uris``.
         '''
-        return self.mopidy_request('core.tracklist.add', tracks=tracks, at_position=at_position, uri=uri, uris=uris, **options)
+        return self.mopidy_request('core.tracklist.add', tracks=tracks, at_position=at_position, uris=uris, **options)
 
     def get_eot_tlid(self, **options):
         '''The TLID of the track that will be played after the current track.