Adding x-mitre-collection object to stix2 bundle (Python)

[Stephan van Beerschoten <stephan@vanbeerschoten.net>]

Hi there,

I am working with a customer that has their own stix2 FileSystemStore
with stix objects focused on their own platform. They created their
own types. All json files pass the stix2 validator. I am trying to
load this into Workbench to make managing this data easier.

However, when I create a python script to create a bundle, I am having
a hard time figuring out how to (properly) add the required
x-mitre-collection object that Workbench complains about. I've tried a
few different ways. Some make the Docker loaded workbench log 500
errors, but no errors are logged.

I even went as far as to ask ChatGPT for input, but that didn't fare
much better.
I would appreciate any pointers or sample code.

Stephan