input: Write a python function to check if a given string is a palindrome.
  assert is_palindrome("Racecar") == True
  assert is_palindrome("Python") == False
  assert is_palindrome("A man a plan a canal Panama") == False
output: def is_palindrome(s: str) -> bool:
      s = s.lower().replace(" ", "")
      return s == s[::-1]