Add is_valid_currency_code row-level check

[SreeramaYeshwanthGowd]

Changes

Adds a new row-level check is_valid_currency_code(column, code_format="alphabetic") that validates values against the ISO 4217 currency codes. ISO 4217 defines a three-letter alphabetic code (e.g. USD) and a three-digit numeric code (e.g. 840); both are supported via the code_format argument ("alphabetic" default, or "numeric"). Validation is a case-sensitive membership test; null values pass with no violation reported.

The code lists are embedded as module-level frozensets generated from the ISO 4217 standard data in the pycountry package (dev-time generation; the regeneration steps are in a comment). The implementation follows the existing pattern-validator checks such as is_valid_email and is_valid_national_id.

Linked issues

Resolves #1340

Tests

• manually tested

• added unit tests

• added integration tests

• added end-to-end tests

• added performance tests

• Unit tests in tests/unit/test_row_checks.py cover the auto-generated column name (default and numeric) and code_format validation (None, non-string, unsupported value).

• Integration tests in tests/integration/test_row_checks.py cover both the alphabetic and numeric formats (valid, invalid, case-sensitive, empty and null cases) plus column-expression input.

• is_valid_currency_code is also added to tests/resources/all_row_checks.yaml and the "all checks" integration tests (test_apply_checks_all_checks_as_yaml, test_apply_checks_all_row_checks_as_yaml_with_streaming, and test_apply_checks_all_checks_using_classes).

• A performance benchmark (test_benchmark_is_valid_currency_code) is added under tests/perf/.

Documentation and Demos

• added/updated demos
• added/updated docs
• added/updated agent skills

docs/dqx/docs/reference/quality_checks.mdx gets a reference-table entry and YAML plus programmatic (DQRowRule) usage examples.

[IvannKurchenko]

Thank you for the contribution.

Active ISO 4217 alpha-3 currency codes,

I'm having hard times finding the notion of alpha-3 in ISO 4217 standard, are you sure it is present there? The standard supports alphanumeric and numeric codes, would it be possible to support both of lists?

derived from the CLDR currency data bundled with Babel:

It might be a better idea to use official resources for standard values list - https://www.iso.org/iso-4217-currency-codes.html.

[IvannKurchenko]

It might not a bad idea to validate ISO 4217 currency alpha code and numeric code. Either by argument or as separate method.

[IvannKurchenko]

I doubt the notion of alpha-3 is present in ISO-4217. Can you double check the standard or wiki page, please?

[SreeramaYeshwanthGowd]

@IvannKurchenko thanks for the review, good points. You're right that ISO 4217 uses alphabetic and numeric codes rather than the alpha-3 term, so I fixed the wording and added a code_format argument to validate either the alphabetic or the numeric code. I also switched the embedded list to pycountry, which packages the official ISO 4217 standard data, and rebased on main.

[SreeramaYeshwanthGowd]

@IvannKurchenko following your earlier note on using official sources, I moved the currency code lists into resource files loaded with importlib.resources, and referenced the official ISO 4217 source (https://www.iso.org/iso-4217-currency-codes.html) in the docstring and docs. Both the alphabetic and numeric formats have unit and integration tests.

[IvannKurchenko]

Thank you for all your efforts. I don't have further feedback from my end. Please, wait for approval from other reviewers.