Add payment calendars example notebook

[ryangarvey]

Pull Request Checklist

• [x] Changes follow the style guide
• [x] Tests pass
• [x] Raised the PR against the develop branch

Description of the PR

Describe the code changes for the reviewers, explain the solution you have provided and how it fixes the issue

[review-notebook-app[bot]]

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[hanialsibai]

/LGTM