Transform the CapitainsCtsPassage in XML string

        :param args: Ordered arguments for etree.tostring() (except the first one)
        :param kwargs: Named arguments
        :return:

def tostring(self, *args, **kwargs):
        """ Transform the CapitainsCtsPassage in XML string

        :param args: Ordered arguments for etree.tostring() (except the first one)
        :param kwargs: Named arguments
        :return:
        """
        return etree.tostring(self.resource, *args, **kwargs)