code: func (v *TreeView) GetSelection() (*TreeSelection, error) {
  	c := C.gtk_tree_view_get_selection(v.native())
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	return wrapTreeSelection(glib.Take(unsafe.Pointer(c))), nil
  }
docs: // GetSelection is a wrapper around gtk_tree_view_get_selection().