List initialisation as an empty list, not None
List initialisation as an empty list, not None

tiborsimko/invenio-records,tiborsimko/invenio-records,inveniosoftware/invenio-search,inveniosoftware/invenio-search,tiborsimko/invenio-search,tiborsimko/invenio-search,inveniosoftware/invenio-records,inveniosoftware/invenio-records