gbfs_nextbike_vehicle_availabilities fails

[ThorstenFroehlinghaus]

The ipl-transformer-proxy-1 logs shows this for several nextbike feeds:

[05:20:57.897] Addon error: list index out of range
Traceback (most recent call last):
File "/app/app/app.py", line 67, in response
json_data = json_converter.convert(data=json_data, path=flow.request.path)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/app/app/converters/gbfs_nextbike_vehicle_availabilities.py", line 44, in convert
return self._convert_station_status(system_id, data, path)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/app/app/converters/gbfs_nextbike_vehicle_availabilities.py", line 63, in _convert_station_status
update_stations_availability_status(data['data']['stations'], vehicles)
File "/app/app/utils/gbfs_util.py", line 44, in update_stations_availability_status
default_vehicle_types_available = [{'vehicle_type_id': vehicles[0]['vehicle_type_id'], 'count': 0}]
~~~~~~~~^^^
IndexError: list index out of range
172.28.5.14:54564: GET https://gbfs.nextbike.net/maps/gbfs/v2/nextbike_vn/de/s…
<< 200 OK 2.8k
172.28.5.14:54552: GET https://stables.donkey.bike/api/public/gbfs/2/donkey_th…
<< 200 OK 704b
....

This might be the reason for the following validation messages:

        "station_status": {
            "file": "station_status",
            "required": false,
            "exists": true,
            "errorsCount": 344,
            "version": "2.3",
            "errors": [
                {
                    "schemaPath": "#/properties/data/properties/stations/items",
                    "violationPath": "#/data/stations/0",
                    "message": "#/data/stations/0: required key [vehicle_types_available] not found"
                },
                {
                    "schemaPath": "#/properties/data/properties/stations/items",
                    "violationPath": "#/data/stations/1",
                    "message": "#/data/stations/1: required key [vehicle_types_available] not found"
                },

...