def _get_node_change_list(exploration_id, property_name, new_value):
    return [{
        'cmd': collection_domain.CMD_EDIT_COLLECTION_NODE_PROPERTY,
        'exploration_id': exploration_id,
        'property_name': property_name,
        'new_value': new_value
    }]
If you forget, you'll get bad errors.
dataset/ETHPy150Open oppia/oppia/core/domain/collection_services_test.py/_get_node_change_list--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/tests/modeltests/transactions/tests.py/TransactionTests.test_manually_managed_mistake