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