code: func (v *Grid) GetChildAt(left, top int) (*Widget, error) {
  	c := C.gtk_grid_get_child_at(v.native(), C.gint(left), C.gint(top))
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	obj := glib.Take(unsafe.Pointer(c))
  	return wrapWidget(obj), nil
  }
docs: // GetChildAt() is a wrapper around gtk_grid_get_child_at().