new_contents: 
  
  def is_palindrome(mapping):
      """ Returns true if mapping is a palindrome
  
      >>> is_palindrome('otto')
      True
      >>> is_palindrome('ottof')
      False
      """
      mapping = list(mapping)
      for x in mapping:
          y = mapping.pop()
          if x == y:
              return True
          else:
              break
      return False
  
  
  if __name__ == '__main__':
      import doctest
      doctest.testmod()
  
subject: check for palindrome