Appending a list in a class from a callback function

Hi all,
This is my first post. Usually I can search out answers to my problems but today I'm having a bit of difficulty finding what I'm doing wrong populating a list of MAC addresses from a callback function, all enclosed within a class. The list is always empty on the very last line where I print it out. If I print the contents of the list from within the callback function each time it is raised, it looks correct. I'm having a feeling it has to do with scope or might need a lambda function but I'm foggy on some aspects there. I apologize for my numerous un-pythonic statements. I'm totally self taught and come from using mainly Visual Basic so I can be a bit of a sloppy coder at times. Here's my code: NOTE: This is normally executed on a Raspberry Pi.

import nmap, sys, socket, subprocess

 

class IP_Roam():

    def __init__(self, root_ip="", display_on=False):

        self.mac_list = []

        self.display_on = display_on

        self.router_ip = root_ip

        self.end_ip = ""

 

    def callback_result(self, host, scan_result):

        if self.display_on:

            sys.stdout.write('\rScanning ' + str(host).ljust(15, ' '))

            sys.stdout.flush()

 

        for ip in scan_result['scan']:

 

            try:

                mac = scan_result['scan'][u'' + str(ip)]['addresses'][u'mac']

                if mac:

                    myscan.mac_list.append(mac)

                #ipv4 = scan_result['scan'][u'' + str(ip)]['addresses'][u'ipv4']

            except:

                # This happens when it finds itself

                pass