* methods now export __func__ instead of im_func for getting the function
  out of a method closure
* however classes no longer return unbound methods in py3k and instead
  return the actual function
* in python 2 we use im_func when getting the function from the vfunc closure
* in py3k we simply assign vfunc to the function

https://bugzilla.gnome.org/show_bug.cgi?id=615872