@abc.abstractmethod
    def db_clear(self, table, record, column):
Only return XFormInstances, not duplicates or errors
dataset/ETHPy150Open openstack/neutron/neutron/agent/ovsdb/api.py/API.db_clear--crossover with--dataset/ETHPy150Open dimagi/commcare-hq/corehq/ex-submodules/couchforms/filters.py/instances