text: class Solution(object):
      def reverseStr(self, s, k):
          """
          :type s: str
          :type k: int
          :rtype: str
          """
          s = list(s)
          for i in range(0, len(s), 2*k):
              s[i:i+k] = reversed(s[i: i+k])
          return ''.join(s)
  