input: 
  def is_palindrome(s):
      """Checks if the given string is a palindrome.
      A palindrome is a string that reads the same backward as forward.
      The function ignores case differences.
      
      >>> is_palindrome("racecar")
      True
      >>> is_palindrome("hello")
      False
      >>> is_palindrome("Madam")
      True
      """
      s = s.lower()
      return s == s[::-1]
  
  print(is_palindrome("racecar"))
  
output:     s = s.lower()
      return s == s[::-1]