def new_pos(self, html_div):
        """factory method pattern"""
        pos = self.Position(self, html_div)
        pos.bind_mov()
        self.positions.append(pos)
        return pos
def new_pos ( self , html_div ) : pos = self . Position ( self , html_div ) pos . bind_mov ( ) self . positions . append ( pos ) return pos
factory method pattern