DataSite.get_repo_for_entity_type calls DataSite.entity_source. This method is not implemented, hence it ends up in BaseSite.__getattr__ with the only purpose:

Delegate undefined methods calls to the Family object.

.. versionchanged:: 9.0
   Only delegate to public Family methods which have ``code`` as
   first parameter.

This is where inspect kicks in.

Perhaps there could be some caching layer.

In T413398#11487420, @matej_suchanek wrote:

Perhaps there could be some caching layer.

Maybe a conceptional change would be more appropriate e,g, having a set or dict within the Family class which holds methods which can be delegated. Instead inspecting the Family methods a simple lookup would do the job. Sample:

class Family:
    delegated_methods = {
        'foo',
        'bar',
        'baz',
    }

Change #1222701 had a related patch set uploaded (by Xqt; author: Xqt):

[pywikibot/core@master] [IMPR] BaseSite.__getattr__: Use direct __code__ inspection for performance

https://gerrit.wikimedia.org/r/1222701

Change #1222701 merged by jenkins-bot:

[pywikibot/core@master] [IMPR] BaseSite.__getattr__: Use direct __code__ inspection for performance

https://gerrit.wikimedia.org/r/1222701