How to use the exabgp.protocol.ip.IP.unpack function in exabgp

def unpack (cls, data):
		rd = RouteDistinguisher.unpack(data[:8])
		esi = ESI.unpack(data[8:18])
		iplen = ordinal(data[18])

		if iplen not in (32,128):
			raise Notify(3,5,"IP length field is given as %d in current Segment, expecting 32 (IPv4) or 128 (IPv6) bits" % iplen)

		ip = IP.unpack(data[19:19+(iplen//8)])

		return cls(rd,esi,ip,data)

def unpack (cls,data,length):
		if len(data) == 4:
			# IPv4 address
			addr = IP.unpack(data[:4])
		elif len(data) == 16:
			# IPv6
			addr = IP.unpack(data[:16])
		else:
			raise Notify(3,5, "Error parsing OSPF Forwarding Address. Wrong size")
		return cls(addr=addr)

def next_hop (self, name, command, tokens):
		if self.scope.content[-1]['announce'][-1].attributes.has(Attribute.CODE.NEXT_HOP):
			return self.error.set(self.syntax)

		try:
			# next-hop self is unsupported
			ip = tokens.pop(0)
			if ip.lower() == 'self':
				if 'local-address' in self.scope.content[-1]:
					la = self.scope.content[-1]['local-address']
				elif self._nexthopself:
					la = self._nexthopself
				else:
					return self.error.set('next-hop self can only be specified with a neighbor')
				nh = IP.unpack(la.pack())
			else:
				nh = IP.create(ip)

			change = self.scope.content[-1]['announce'][-1]
			nlri = change.nlri
			afi = nlri.afi
			safi = nlri.safi

			nlri.nexthop = nh

			if afi == AFI.ipv4 and safi in (SAFI.unicast,SAFI.multicast):
				change.attributes.add(Attribute.unpack(NextHop.ID,NextHop.FLAG,nh.packed,None))
				# NextHop(nh.ip,nh.packed) does not cache the result, using unpack does
				# change.attributes.add(NextHop(nh.ip,nh.packed))

			return True

def unpack (cls,data,length):
		if len(data) == 4:
			# IPv4 address
			terid = IP.unpack(data[:4])
		elif len(data) == 16:
			# IPv6
			terid = IP.unpack(data[:16])
		return cls(terid=terid)

def __init__ (self, afi=AFI.ipv4,safi=SAFI.flow_ip,nexthop=None,rd=None):
		NLRI.__init__(self,afi,safi)
		self.rules = {}
		self.action = OUT.ANNOUNCE
		self.nexthop = IP.unpack(nexthop) if nexthop else NoIP
		self.rd = rd
		self.unique = unique.next()

def unpack (cls, data):
		if len(data) == 4:
			# IPv4 address
			addr = IP.unpack(data[:4])
		elif len(data) == 16:
			# IPv6
			addr = IP.unpack(data[:16])
		return cls(iface_addr=addr)

def unpack (cls, data, igp):
		dtype, dlength = unpack('!HH',data[0:4])
		if dtype not in NODE_TLVS.keys():
			raise Exception("Unknown Node Descriptor Sub-TLV")
		# OSPF Area-ID
		if dtype == 514:
			return cls(
				node_id=IP.unpack(data[4: 4 + dlength]),
				dtype=dtype,
				packed=data[:4+dlength]
			), data[4 + dlength:]
		# IGP Router-ID: The TLV size in combination with the protocol
		# identifier enables the decoder to determine the type
		# of the node: sec 3.2.1.4.
		elif dtype == 515:
			# OSPFv{2,3} non-pseudonode
			if (igp == 3 or igp == 6) and dlength == 4:
				r_id = IP.unpack(data[4: 4 + 4])
				return cls(
					node_id=r_id,
					dtype=dtype,
					packed=data[:4+dlength]
				), data[4 + 4:]
			# OSPFv{2,3} LAN pseudonode

def unpack (cls, data):
		if len(data) == 4:
			# IPv4 address
			addr = IP.unpack(data[:4])
		elif len(data) == 16:
			# IPv6
			addr = IP.unpack(data[:16])
		return cls(iface_addr=addr)