def target_urls(self, year=None):
        raise NotImplementedError()
Given a subject string, tries to match a major and/or
dataset/ETHPy150Open openelections/openelections-core/openelex/base/datasource.py/BaseDatasource.target_urls--crossover with--dataset/ETHPy150Open rcbops/glance-buildpackage/glance/api/middleware/version_negotiation.py/VersionNegotiationFilter._match_version_string