code: def short_key():
      
      firstlast = list(ascii_letters + digits)
      middle = firstlast + list('-_')
      return ''.join((
          choice(firstlast), choice(middle), choice(middle),
          choice(middle), choice(firstlast),
      ))
docs: Generate a short key.
  
      >>> key = short_key()
      >>> len(key)
      5