code: def in6_getnsmac(a): # return multicast Ethernet address associated with multicast v6 destination
      
  
      a = struct.unpack('16B', a)[-4:]
      mac = '33:33:'
      mac += (':'.join(map(lambda x: '%.2x' %x, a)))
      return mac
docs: Return the multicast mac address associated with provided
      IPv6 address. Passed address must be in network format.