The vast majority of Rhythmbox plugins fail to load when I try to activate them. Here's the output generated when I try to load the cover art plugin:

** Message: pygobject_register_sinkfunc is deprecated (GstObject)
Traceback (most recent call last):
  File "/usr/lib64/rhythmbox/plugins/artdisplay/", line 89, in <module>
    class FadingImage (Gtk.Misc):
  File "/usr/lib64/python2.7/site-packages/gi/", line 208, in __init__
    super(GObjectMeta, cls).__init__(name, bases, dict_)
  File "/usr/lib64/python2.7/site-packages/gi/_gobject/", line 65, in __init__
  File "/usr/lib64/python2.7/site-packages/gi/_gobject/", line 119, in _type_register
    type_register(cls, namespace.get('__gtype_name__'))
TypeError: Error when calling the metaclass bases
    could not get typecode from object

(rhythmbox:4340): libpeas-WARNING **: Error loading plugin 'artdisplay'
I can't quite tell if this is an error with Rhythmbox, GObject, the python bindings, or something else. Any tips?