intro-mdp/mission01/netconf_functions.py doesn't handle multiple addresses

[mbrainar]

When running the solution, I get the following error:

Device: ios-xe-mgmt.cisco.com
  Interface: GigabitEthernet2
Traceback (most recent call last):
  File "netconf_configure_ips.py", line 62, in <module>
    check_ip(device)
  File "/Users/mbrainar/coding/DevNet/dnav3-code/intro-mdp/mission01/netconf_functions.py", line 81, in check_ip
    ipv4["ip"], ipv4["config"]["prefix-length"]
TypeError: list indices must be integers or slices, not str

I believe it is because the instance of ios-xe-mgmt.cisco.com has multiple addresses configured on GigabitEthernet2:

<ipv4 xmlns="http://openconfig.net/yang/interfaces/ip">
                                                        <addresses>
                                                                <address>
                                                                        <ip>10.255.255.1</ip>
                                                                        <config>
                                                                                <ip>10.255.255.1</ip>
                                                                                <prefix-length>24</prefix-length>
                                                                        </config>
                                                                </address>
                                                                <address>

                                                                        <ip>10.255.255.10</ip>
                                                                        <config>
                                                                                <ip>10.255.255.10</ip>
                                                                                <prefix-length>31</prefix-length>
                                                                        </config>
                                                                </address>
                                                                <address>
                                                                        <ip>10.255.255.12</ip>
                                                                        <config>
                                                                                <ip>10.255.255.12</ip>
                                                                                <prefix-length>24</prefix-length>
                                                                        </config>
                                                                </address>
                                                        </addresses>
                                                </ipv4>

[einarnn]

Just an FYI, but the openconfig model in theory allows multiple IP addresses on a subinterface. The first should be assigned as the primary IP and other should be added as secondary IP addresses. However, the problem above seems to be more about a Python coding error.