docs: def in6_ifaceidtomac(ifaceid):
      """
      Extract the mac address from provided iface ID. Iface ID is provided
      in printable format ("XXXX:XXFF:FEXX:XXXX", eventually compressed). None
      is returned on error.
      """
      try:
          # Set ifaceid to a binary form
          ifaceid = inet_pton(socket.AF_INET6, "::" + ifaceid)[8:16]
      except Exception:
          return None
      if ifaceid[3:5] != b'\xff\xfe':  # Check for burned-in MAC address
          return None
  
      # Unpacking and converting first byte of faceid to MAC address equivalent
      first = struct.unpack("B", ifaceid[:1])[0]
      ulbit = 2 * [1, '-', 0][first & 0x02]
      first = struct.pack("B", ((first & 0xFD) | ulbit))
      # Split into two vars to remove the \xff\xfe bytes
      oui = first + ifaceid[1:3]
      end = ifaceid[5:]
      # Convert and reconstruct into a MAC Address
      mac_bytes = ["%.02x" % orb(x) for x in list(oui + end)]
      return ":".join(mac_bytes)