input: Write a python function to check if a given string is a palindrome.
  assert isPalindrome("madam") == True
  assert isPalindrome("racecar") == True
  assert isPalindrome("hello") == False
  assert isPalindrome("Aba") == True
output: def isPalindrome(s):
      s = s.lower()
      return s == s[::-1]