def get_all_test_metadata_keys(session=None):
    session = session or get_session()
    keys = session.query(models.TestMetadata.key).distinct().all()
    return [key[0] for key in keys]
Provides indexed access, (e.g. 'columns[0]').
dataset/ETHPy150Open openstack-infra/subunit2sql/subunit2sql/db/api.py/get_all_test_metadata_keys--crossover with--dataset/ETHPy150Open scanny/python-pptx/pptx/shapes/table.py/_ColumnCollection.__getitem__