Append a new ``<p:sp>`` shape to the group/shapetree having the
        properties specified in call.

def add_autoshape(self, id_, name, prst, x, y, cx, cy):
        """
        Append a new ``<p:sp>`` shape to the group/shapetree having the
        properties specified in call.
        """
        sp = CT_Shape.new_autoshape_sp(id_, name, prst, x, y, cx, cy)
        self.insert_element_before(sp, 'p:extLst')
        return sp