code: def isPalindrome(self, s):
      """
      :type s: str
      :rtype: bool
      """
      alnum_s = [t.lower() for t in s if t.isalnum()]
      ls = len(alnum_s)
      if ls <= 1:
          return True
      mid = ls / 2
      for i in range(mid):
          if alnum_s[i] != alnum_s[ls - 1 - i]:
              return False
      return True
  
label_desc: Use image node_id 1 for calling the Solution obj's underlying member method code with example usage: obj.isPalindrome(s) and returns: True, True, False