code: func SeparatorToolItemNew() (*SeparatorToolItem, error) {
  	c := C.gtk_separator_tool_item_new()
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	return wrapSeparatorToolItem(glib.Take(unsafe.Pointer(c))), nil
  }
docs: // SeparatorToolItemNew is a wrapper around gtk_separator_tool_item_new().