def categories(self):
        """
        Returns a |category.Categories| sequence object containing
        a |category.Category| object for each of the category labels
        associated with this plot. The |category.Category| class derives from
        ``str``, so the returned value can be treated as a simple sequence of
        strings for the common case where all you need is the labels in the
        order they appear on the chart. |category.Categories| provides
        additional properties for dealing with hierarchical categories when
        required.
        """
        return Categories(self._element)