input: Write a function to check if a given string is a palindrome. The function should return True if the string is a palindrome and False otherwise. The function should ignore case sensitivity and spaces.
  
  def is_palindrome(s):
      s = s.lower().replace(" ", "")
      return s == s[::-1]
  
  assert is_palindrome("racecar") == True
  assert is_palindrome("A man a plan a canal Panama") == True
  assert is_palindrome("hello") == False
  assert is_palindrome("") == True
output: def is_palindrome(s):
      s = s.lower().replace(" ", "")
      return s == s[::-1]