问将列表存储在另一个列表中的列表中

EN

{
    "success": true,
    "routes": [
        {
            "_id": "613cc90623db8f3418f59f50",
            "transit": [
                "Addis Ababa",
                "Gondar"
            ],
            "startingPlace": {
                "country": "Ethiopia",
                "city": "Addis Ababa"
            },
            "destination": {
                "country": "Ethiopia",
                "city": "Addis Ababa"
            },
            "distance": 55,
            "__v": 0,
            "schedule": [
                {
                    "_id": "613e200446560f0508778adf",
                    "boardingDate": "2020-01-01T00:00:00.000Z",
                    "arrivalDate": "2020-02-01T00:00:00.000Z",
                    "driverAssistantId": "612de5d3cf56fc27e8abf629",
                    "routeId": "613cc90623db8f3418f59f50",
                    "__v": 0
                }
            ]
        }
    ]
}

Future<List<Schedule>> searchSchedule(SearchScheduleModel model) async {
  String token = await getToken();
  Map<String, String> headers = {
    "Content-Type": "application/json",
    'Authorization': 'Bearer $token'
  };
  final allPlacesURl = Uri.parse("$ipAddress/common/searchBySpAndDes");
  var body = searchScheduleModelToJson(model);

  var response = await http.post(allPlacesURl, headers: headers, body: body);
  if (response.statusCode == 200) {
    var body = schedulesModelFromJson(response.body);
    List<Route> route = body.routes;
    List<Schedule> schedules = [];

    //the error is shown here, how can i map a list within alist

    schedules = route.map((e) => e.schedule);

    return schedules;
  }
  return json.decode(response.body);
}

A value of type 'Iterable<List<Schedule>>' can't be assigned to a variable of type 'List<Schedule>'.