docs: added an example how to use Buckets API

[bednar]

Closes #210

Proposed Changes

Added an example how to use Buckets API.

Checklist

• CHANGELOG.md updated
• Rebased/mergeable
• pytest tests completes successfully
• Commit messages are in semantic format
• Sign CLA (if not already signed)

[codecov]

Codecov Report

Merging #213 (579921e) into master (0a78566) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #213   +/-   ##
=======================================
  Coverage   89.94%   89.94%           
=======================================
  Files          26       26           
  Lines        1969     1969           
=======================================
  Hits         1771     1771           
  Misses        198      198           

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