def import_databases(self, databaseinfra):
        raise NotImplementedError()
Tests the case where user has no created or edited explorations.
dataset/ETHPy150Open globocom/database-as-a-service/dbaas/drivers/base.py/BaseDriver.import_databases--crossover with--dataset/ETHPy150Open oppia/oppia/core/domain/user_jobs_one_off_test.py/UserContributionsOneOffJobTests.test_null_case