def get_notify_subject(self, ar, obj):
        return None
Creates a list of DUs from URL list
dataset/ETHPy150Open lsaffre/lino/lino/core/actions.py/NotifyingAction.get_notify_subject--crossover with--dataset/ETHPy150Open saga-project/BigJob/pilot/impl/pilotdata_manager.py/DataUnitItem.create_data_unit_from_urls