def _verify_region_def_schema(region_defs):
    """Ensure region_defs dictionary conforms to expected schema."""
    for i, (region_name, crit_list) in enumerate(region_defs.items()):
        assert isinstance(crit_list, list)
        for crit in crit_list:
            assert isinstance(crit, dict)
            for crit_type, crit_dict in crit.items():
                assert crit_type in ['bounds', 'match']
