any_of='use-first' not working

[kurtrwall]

Describe the bug
Btw, great library, thanks for making it!

I'm trying to use this with draft 6 jsonschema (Microsoft's AdaptiveCard schema, and I'm still getting:

NotImplementedError: anyOf is not supported as bare property (workarounds available by setting any_of flag)

Example Schema and code

import python_jsonschema_objects as pjs
import requests
schema = requests.get('https://adaptivecards.io/schemas/adaptive-card.json').json()
ns = builder.build_classes(any_of='use-first')
...snip
NotImplementedError: anyOf is not supported as bare property (workarounds available by setting any_of flag)

Expected behavior
The schema was parsed and the classes were generated.

[cwacek]

Hey @kurtrwall, I've got a PR that fixes your issue, but it highlighted a different one in the adaptive-card.json schema. Do you happen to know what one is supposed to do with these invalid properties: https://github.com/cwacek/python-jsonschema-objects/pull/301/files#diff-3c302bf352d3c575ff7e419df154d494c77f837be3f00e9e4b350b0ec7d99779R35-R43

As far as I can tell reading the spec, at a minimum you are required to provide the type key for any properties, and those ones are just empty objects. The library is now bailing out attempting to parse the schema because there's no definition.

[cwacek]

This might be a broader issue with Microsoft's AdaptiveCard: microsoft/AdaptiveCards#8943

Going to mark as xfail for now, so I can merge the PR because the underlying issue was real.

[kurtrwall]

Thanks for looking at this, hopefully they address it soon or at least take a look at that linked issue...