stop_vmss action doesn't work

[okumurays]

I tried to use stop_vmss action, but it doesn't work.
debug log is following.

・[32m[2021-08-01 21:18:31 INFO] [activity:161] [39m Action: stop-vmss
・[36m[2021-08-01 21:18:31 DEBUG] [python:34] [39m Activity 'stop-vmss' loaded from '\chaostkcheck\lib\site-packages\chaosazure\vmss\actions.py'
・[36m[2021-08-01 21:18:31 DEBUG] [actions:143] [39m Starting stop_vmss: configuration='{'azure_subscription_id': '1e6068d8-cfa7-4b67-9f26-d134c9b026cd'}', filter='None'
・[33m[2021-08-01 21:18:31 WARNING] [cloud:16] [39m Azure cloud not provided. Using AZURE_PUBLIC_CLOUD as default
・[36m[2021-08-01 21:18:32 DEBUG] [fetcher:54] [39m Fetched VMSS: ['chaos-test']
・[33m[2021-08-01 21:18:32 WARNING] [cloud:16] [39m Azure cloud not provided. Using AZURE_PUBLIC_CLOUD as default
・[36m[2021-08-01 21:18:32 DEBUG] [activity:235] [39m Activity failed
    Traceback (most recent call last):
      File "\chaostkcheck\lib\site-packages\chaoslib\provider\python.py", line 55, in run_python_activity
        return func(**arguments)
      File "\chaostkcheck\lib\site-packages\chaosazure\vmss\actions.py", line 151, in stop_vmss
        instances = fetch_instances(scale_set, instance_criteria,
      File "\chaostkcheck\lib\site-packages\chaosazure\vmss\fetcher.py", line 16, in fetch_instances
        instance = __random_instance_from(
      File "\chaostkcheck\lib\site-packages\chaosazure\vmss\fetcher.py", line 86, in __random_instance_from
        instances = __fetch_vmss_instances(
      File "\chaostkcheck\lib\site-packages\chaosazure\vmss\fetcher.py", line 68, in __fetch_vmss_instances
        first_page = pages.advance_page()
    AttributeError: 'ItemPaged' object has no attribute 'advance_page'
    
    During handling of the above exception, another exception occurred:
    
    Traceback (most recent call last):
      File "\chaostkcheck\lib\site-packages\chaoslib\activity.py", line 228, in run_activity
        result = run_python_activity(activity, configuration, secrets)
      File "\chaostkcheck\lib\site-packages\chaoslib\provider\python.py", line 57, in run_python_activity
        raise ActivityFailed(
      File "\chaostkcheck\lib\site-packages\chaoslib\provider\python.py", line 55, in run_python_activity
        return func(**arguments)
      File "\chaostkcheck\lib\site-packages\chaosazure\vmss\actions.py", line 151, in stop_vmss
        instances = fetch_instances(scale_set, instance_criteria,
      File "\chaostkcheck\lib\site-packages\chaosazure\vmss\fetcher.py", line 16, in fetch_instances
        instance = __random_instance_from(
      File "\chaostkcheck\lib\site-packages\chaosazure\vmss\fetcher.py", line 86, in __random_instance_from
        instances = __fetch_vmss_instances(
      File "\chaostkcheck\lib\site-packages\chaosazure\vmss\fetcher.py", line 68, in __fetch_vmss_instances
        first_page = pages.advance_page()
    chaoslib.exceptions.ActivityFailed: AttributeError: 'ItemPaged' object has no attribute 'advance_page'
・[31m[2021-08-01 21:18:32 ERROR] [activity:188] [39m   => failed: AttributeError: 'ItemPaged' object has no attribute 'advance_page'

Currently there is no advance_page attribute in ItemPaged class
https://docs.microsoft.com/en-us/python/api/azure-core/azure.core.paging.itempaged?view=azure-python

My environment is here

・OS：Windows 10 Home (build 19043.1110)
・Python：3.9.6
・packages
azure-common             1.1.27
azure-core               1.16.0
azure-identity           1.6.0
azure-mgmt-compute       20.0.0
azure-mgmt-core          1.3.0
azure-mgmt-resourcegraph 8.0.0
azure-mgmt-web           3.0.0
chaostoolkit             1.9.1
chaostoolkit-azure       0.10.0
chaostoolkit-lib         1.19.0

I think the following code is one way to fix it:

    result = client.virtual_machine_scale_set_vms.list(
        choice['resourceGroup'], choice['name'])
    for item in result:
        logger.info(item.name)
        vmss_instances.append(item)

But we also need to consider paging.