Summary

Add support for validating ISO 4914 Unique Product Identifiers (UPIs).

A UPI is a 12-character financial identifier for over-the-counter derivative products. The implementation validates:

• the mandatory QZ prefix;
• the restricted alphanumeric alphabet;
• the 12-character length; and
• the ISO 7064 Mod 31, 30 check character.

It also provides the standard compact(), validate(), is_valid(), and calc_check_digit() interfaces.

References

• ISO 4914
• Derivatives Service Bureau UPI information

Testing

• Added module documentation examples.
• Added a dedicated doctest covering normalization, prefix, alphabet, length, and checksum validation.
• Included four published valid UPIs sourced from the DSB, CME Group, and official regulatory material.
• The new module achieves 100% test coverage.
• Full test suite: 407 passed, 9 skipped.
• Flake8 and strict mypy checks pass.

Publicly documented real UPI examples appear to be limited, so the test set currently contains four published examples. The official DSB archive requires registration, I can look into that if we need more examples.