diff --git a/mopidy/core/tracklist.py b/mopidy/core/tracklist.py
index 22e741da..125843b2 100644
--- a/mopidy/core/tracklist.py
+++ b/mopidy/core/tracklist.py
@@ -432,14 +432,17 @@ class TracklistController(object):
         return self._tl_tracks[start:end]
 
     def mark_playing(self, tl_track):
+        """Private method used by :class:`mopidy.core.PlaybackController`."""
         if self.random and tl_track in self._shuffled:
             self._shuffled.remove(tl_track)
 
     def mark_unplayable(self, tl_track):
+        """Private method used by :class:`mopidy.core.PlaybackController`."""
         if self.random and self._shuffled:
             self._shuffled.remove(tl_track)
 
     def mark_played(self, tl_track):
+        """Private method used by :class:`mopidy.core.PlaybackController`."""
         if not self.consume:
             return False
         self.remove(tlid=tl_track.tlid)