def top_i_answer(self, i):
for j, a in enumerate(self.answers):<EOL><INDENT>if j == i - <NUM_LIT:1>:<EOL><INDENT>return a<EOL><DEDENT><DEDENT>
获取排名某一位的答案.

        :param int i: 要获取的答案的排名
        :return: 答案对象，能直接获取的属性参见answers方法
        :rtype: Answer