new_contents: import re
  from functools import reduce
  
  def mac_to_hostid(mac):
    int_mac = list(map(lambda x: int(x, 16), mac.split(":")))
    int_mac[0] ^= 2
    bytes = map(lambda x: "%02x" % x, int_mac[0:3] + [0xff, 0xfe] + int_mac[3:])
    return reduce(lambda a, i:
                    [a[0] + ("" if i == 0 else ":") + a[1] + a[2]] + a[3:],
                  range(0, 4),
                  [""] + list(bytes)
                 )
  
  
subject: add hostid module with mac_to_hostid function