@@ -10,7 +10,10 @@
 import struct
 import socket
 import time
-from scapy.packet import Packet, bind_layers, bind_bottom_up
+
+from typing import Tuple, Any
+
+from scapy.packet import Packet, bind_layers, bind_bottom_up, Packet_metaclass
 from scapy.fields import IntField, ShortEnumField, XByteField
 from scapy.layers.inet import TCP
 from scapy.supersocket import StreamSocket
# This file is part of Scapy
# See http://www.secdev.org/projects/scapy for more information
# Copyright (C) Nils Weiss <nils@we155.de>
# This program is published under a GPLv2 license

# scapy.contrib.description = HSFZ - BMW High-Speed-Fahrzeug-Zugang
# scapy.contrib.status = loads


import struct
import socket
import time
from scapy.packet import Packet, bind_layers, bind_bottom_up
from scapy.fields import IntField, ShortEnumField, XByteField
from scapy.layers.inet import TCP
from scapy.supersocket import StreamSocket
from scapy.contrib.automotive.uds import UDS
from scapy.contrib.isotp import ISOTP
from scapy.error import Scapy_Exception
from scapy.data import MTU


"""
BMW HSFZ (High-Speed-Fahrzeug-Zugang / High-Speed-Car-Access).
BMW specific diagnostic over IP protocol implementation.
The physical interface for this connection is called ENET.
"""

# #########################HSFZ###################################


class HSFZ(Packet):
    name = 'HSFZ'
    fields_desc = [
        IntField('length', None),
        ShortEnumField('type', 1, {0x01: "message",
                                   0x02: "echo"}),
        XByteField('src', 0),
        XByteField('dst', 0),
    ]

    def hashret(self):
        hdr_hash = struct.pack("B", self.src ^ self.dst)
        pay_hash = self.payload.hashret()
        return hdr_hash + pay_hash

    def answers(self, other):
        if other.__class__ == self.__class__:
            return self.payload.answers(other.payload)
        return 0

    def extract_padding(self, s):
        return s[:self.length - 2], s[self.length - 2:]

    def post_build(self, pkt, pay):
        """
        This will set the LenField 'length' to the correct value.
        """
        if self.length is None:
            pkt = struct.pack("!I", len(pay) + 2) + pkt[4:]
        return pkt + pay


bind_bottom_up(TCP, HSFZ, sport=6801)
bind_bottom_up(TCP, HSFZ, dport=6801)
bind_layers(TCP, HSFZ, sport=6801, dport=6801)
bind_layers(HSFZ, UDS)


# ########################HSFZSocket###################################


class HSFZSocket(StreamSocket):
    def __init__(self, ip='127.0.0.1', port=6801):
        self.ip = ip
        self.port = port
        s = socket.socket()
        s.connect((self.ip, self.port))
        StreamSocket.__init__(self, s, HSFZ)


class ISOTP_HSFZSocket(HSFZSocket):
    def __init__(self, src, dst, ip='127.0.0.1', port=6801, basecls=ISOTP):
        super(ISOTP_HSFZSocket, self).__init__(ip, port)
        self.src = src
        self.dst = dst
        self.basecls = HSFZ
        self.outputcls = basecls

    def send(self, x):
        if not isinstance(x, ISOTP):
            raise Scapy_Exception(
                "Please provide a packet class based on ISOTP")
        try:
            x.sent_time = time.time()
        except AttributeError:
            pass

        super(ISOTP_HSFZSocket, self).send(
            HSFZ(src=self.src, dst=self.dst) / x)

    def recv(self, x=MTU):
        pkt = super(ISOTP_HSFZSocket, self).recv(x)
        return self.outputcls(bytes(pkt[1]))

The `typing` module isn't available by default on Python 2. But it seems the cryptography module (or one of its dependencies) installs it, making those tests pass.