docs: update example os listing users with python client

[plaguss]

Description

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Closes #3453

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (change restructuring the codebase without changing functionality)
• Improvement (change adding some improvement to an existing functionality)
• Documentation update

How Has This Been Tested

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• Test A
• Test B

Checklist

• I added relevant documentation
• follows the style guidelines of this project
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• I made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
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• I have added relevant notes to the CHANGELOG.md file (See https://keepachangelog.com/)

[nataliaElv]

Sorry, one last change before approving the PR. In the block below assignments[users[idx]['username']].append(record) should change to assignments[users[idx].username].append(record) to work:

# divide your dataset in chunks of the same length as the users list and make the assignments
n = len(users)
chunked_records = [ds[i:i + n] for i in range(0, len(ds), n)]
for chunk in chunked_records:
    for idx, record in enumerate(chunk):
        assignments[users[idx]['username']].append(record)

[plaguss]

No problem, that should be it then :)

[nataliaElv]

Thanks for the contribution @plaguss !