input: Write a python function to check if a given string is a palindrome.
  assert isPalindrome("Mom") == True
  assert isPalindrome("Apple") == False
  assert isPalindrome("Racecar") == True
  assert isPalindrome("Palindrome") == False
output: def isPalindrome(s: str) -> bool:
      s = s.lower()
      return s == s[::-1]