Agency on Maintainable Artifact should be str or Item

[javihern98]

Should the agency property of the Maintainable Artifact be a str (simpler) or an Agency object (more complex)?

[javihern98]

The agency property of MaintainableArtefact was kept as str due to previous discussions of simplicity. On SDMXthon we do use the Agency class to specify it, but costs much more in terms of complexity.
As an intermediate solution, we could generate on-the-fly an Agency object from the str.

def generate_agency(agency_code: str):
    return Agency(
        id=agency_code,
        name=agency_code)

[javihern98]

This should only be used on Writer parser on metadata xml. Solution was to use a Union[str, Agency] on MaintainableArtifact to ensure we can add Agency data to a specific subclass (contacts mainly)