new_contents: class Solution:
      # @param {string} s
      # @return {boolean}
      def isPalindrome(self, s):
          s = ''.join(c.lower() for c in s if c.isalnum())
          i, j = 0, len(s) - 1
          while i < j:
              if s[i] != s[j]:
                  return False
              i += 1
              j -= 1
          
          return True
  
subject: Create ValidPalindrome_002.py