createCustomerGroup method
      
Future<CustomerGroup> 
createCustomerGroup({ 
    
- required CreateCustomerGroup request,
 - String? authToken,
 
Creates a new customer group for a business.
The request must include the name value of the group.
Implementation
Future<CustomerGroup> createCustomerGroup({
  required CreateCustomerGroup request,
  String? authToken,
}) async {
  authToken ??= authenticationService.getCachedToken()?.accessToken;
  Map<String, String> headers = {
    "Authorization": "Bearer ${authToken ?? ""}",
    'Content-Type': 'application/json; charset=UTF-8',
    'Accept': 'application/json',
  };
  Uri endpoint = Uri.https(
      baseUrl, "/v2/customers/groups");
  //print (endpoint.toString());
  var response = await
  http.post(endpoint, body:jsonEncode(request.toJson()), headers: headers);
  if (response.statusCode == 200) {
    print (jsonDecode(response.body));
    return CustomerGroupResponse.fromJson(jsonDecode(response.body)).group!;
  }
  else {
    print (response.body);
    throw CustomerException(statusCode: response.statusCode, message: CustomerGroupResponse.fromJson(jsonDecode(response.body)).errors?[0].detail?.toString());
  }
}