new_contents: def mac_to_lladdr(mac):
       macpieces = []
       mac = mac.replace('-', ':')
       for byte in mac.split(':'):
            macpieces.append(int(byte, 16))
       macpieces[0] = macpieces[0] ^ 2
       llapieces = [(macpieces[0] << 8) + macpieces[1], (macpieces[2] << 8) + 0xff, 0xfe00 + macpieces[3], (macpieces[4] << 8) + macpieces[5]]
       return 'fe80::{:x}:{:x}:{:x}:{:x}'.format(*llapieces)
  
  if __name__ == '__main__':
      import sys
      print(mac_to_lladdr(sys.argv[1]))
  
subject: ADd a sample for converting mac to lla