To bind a signal to a callback, you do something like:

  def my_callback(<signal_args>, foo, bar):
      pass
  my_object.connect("some-signal", my_callback, foo, bar)

If you don't have any user data to pass to your callback, you could do:

  def my_callback(<signal_args>):
      pass
  my_object.connect("some-signal", my_callback)

I would like to be able to do that for the asynchronous functions of grilo, but there doesn't seem to be a way to do that properly. For instance, with the following function:
  guint grl_media_source_search (GrlMediaSource *source,
                                 const gchar *text,
                                 const GList *keys,
                                 guint skip,
                                 guint count,
                                 GrlMetadataResolutionFlags flags,
                                 GrlMediaSourceResultCb callback,
                                 gpointer user_data);
The callback type is:
  typedef void (*GrlMediaSourceResultCb) (GrlMediaSource *source,
                                          guint operation_id,
                                          GrlMedia *media,
                                          guint remaining,
                                          gpointer user_data,
                                          const GError *error);

In python, even if I don't have any user_data to pass, I need to do:
  def my_callback(source, op_id, media, remaining, user_data, error):
      pass
  my_media_source.search("blah", [<some keys>], 0, 0, <some flags>, my_callback, None, err)

I would like to be able to get rid of that user_data param.