filter([[:event_type, '=', 'login'],
[:object_kind, '=', 'arvados#user'],
[:created_at, '>=', threshold_start],
[:created_at, '<', threshold_end]])
filter([[:event_type, '=', 'login'],
[:object_kind, '=', 'arvados#user'],
[:created_at, '>=', threshold_start],
[:created_at, '<', threshold_end]])