How to use fromJson and toJson when json object have inside another object like this in flutter

When i called getall endpoint, its gives me to like below json object and I'm gonna bind that value to a Entity class.But cant assign new values or access response value.Because it have inside the another json object.I will attach that codes below.

I want to know the correct order of create a entity that json object have several object for json object id in flutter

[
    {
        "id": "931992ff-6ec6-43c9-a54c-b1c5601d58e5",
        "sp_id": "062700016",
        "phone_number": "+94716035826",
        "nic": "991040293V",
        "**drivers_license**": {
            "license_id": "12345678",
            "expiry_date": "2023-09-36"
        },
        "user_level": "",
        "gender": "Male",
        "user_sub_type": "app_user",
        "is_fleet_owner": false,
        "fleet_id": "",
        "documents": null,
        "payment_parameters": {
            "account_holder_name": "",
            "bank_name": "",
            "branch_name": "",
            "account_number": "",
            "swift_code": ""
        }
    }
]

I want to create the entity which is bolded in the json calling "drivers_license" object

I tried entity class like thi.,But can't get proper understand how to implement like part of drivers_license above json.

class ServiceProviderModel {
  String id = "";
  String phone_number = "";
  String nic = "";
  String license_id = "";
  String expiry_date = "";
  String gender = "";
  String user_sub_type = "";
  String document_type_1 = "";
  String document_type_2 = "";
  String first_name = "";
  String last_name = "";
  String email = "";
  String profile_pic_url = "";
  String emergency_contact = "";
  String status = "active";

  ServiceProviderModel();

  ServiceProviderModel.fromJson(Map json)
      : id = json['id'],
        phone_number = json['phone_number'],
        nic = json['nic'],
        license_id = json['license_id'],
        gender = json['gender'],
        user_sub_type = json['user_sub_type'],
        document_type_1 = json['document_type_1'],
        document_type_2 = json['document_type_2'],
        first_name = json['first_name'],
        last_name = json['last_name'],
        email = json['email'],
        profile_pic_url = json['profile_pic_url'],
        emergency_contact = json['emergency_contact'],
        expiry_date = json['expiry_date'],
        status = json['status'];

  Map toJson() => {
        'id': id,
        'phone_number': phone_number,
        'nic': nic,
        'license_id': license_id,
        'gender': gender,
        'user_sub_type': user_sub_type,
        'document_type_1': document_type_1,
        'document_type_2': document_type_2,
        'first_name': first_name,
        'last_name': last_name,
        'email': email,
        'profile_pic_url': profile_pic_url,
        'emergency_contact': emergency_contact,
        'expiry_date': expiry_date,
        'status': status,
      };
}

I found a good answer for this question, and I used the below code to solve this issue. This is very simple and clean

class ServiceProviderModel {
  String id = "";
  String phone_number = "";
  String nic = "";
  Map drivers_license = new Map();
  String license_id = "";
  String expiry_date = "";
  String gender = "";
  String user_sub_type = "";
  Map documents = new Map();
  String document_type_1 = "";
  String document_type_2 = "";
  String first_name = "";
  String last_name = "";
  String email = "";
  String profile_pic_url = "";
  String emergency_contact = "";
  String status = "active";

  ServiceProviderModel();

  ServiceProviderModel.fromJson(Map json)
      : id = json['id'],
        phone_number = json['phone_number'],
        nic = json['nic'],
        drivers_license = json['drivers_license'],
        gender = json['gender'],
        user_sub_type = json['user_sub_type'],
        documents = json['documents'],
        first_name = json['first_name'],
        last_name = json['last_name'],
        email = json['email'],
        profile_pic_url = json['profile_pic_url'],
        emergency_contact = json['emergency_contact'],
        status = json['status'];

  Map toJson() =>
      {
        'id': id,
        'phone_number': phone_number,
        'nic': nic,
        'drivers_license': drivers_license,
        'gender': gender,
        'user_sub_type': user_sub_type,
        'documents': documents,
        'first_name': first_name,
        'last_name': last_name,
        'email': email,
        'profile_pic_url': profile_pic_url,
        'emergency_contact': emergency_contact,
        'status': status,
      };
}