在python中如何实现列表中元素的所有排列组合?如输入为['1','2','3']和2输出为['11','12','13','21','22','23','31','32','33']如输入为['1','2','3']和3输出为['111','112','113','121','122','123','131','132','133','211','212','213','221','222','223','231','232','233','311','312','313','321','322','323','331','332','333']