344. 反转字符串python

编写一个函数，其作用是将输入的字符串反转过来。

示例 1:

输入: "hello"
输出: "olleh"

示例 2:

输入: "A man, a plan, a canal: Panama"
输出: "amanaP :lanac a ,nalp a ,nam A"
方法一  

class Solution:
    def reverseString(self, s):
        """
        :type s: str
        :rtype: str
        """
        s = s[::-1]
        return s

　方法二　

class Solution:
    def reverseString(self, s):
        """
        :type s: str
        :rtype: str
        """
        s1 = ''
        for i in range(len(s)-1,-1,-1):
            s1 += s[i]
        return s1