Is it currently (Delphi 12) possible to write in server method parameters some class and receive it from simple JSON?

Now I have:

type
    TTestParam = class
        fVal1: Integer;
    end;

    {$METHODINFO ON}
    TTest = class(TDSServerModule)
    strict private
    public
        function updateTest(param: TJsonObject): TTestParam;
    end;
    {$METHODINFO OFF}

implementation

function TTest.updateTest(param: TJsonObject): TTestParam;
var
    lParam: TTestParam;
begin
    lParam := TTestParam.Create;
    try
        TJson.JsonToObject(lParam, param);

        Result := TTestParam.Create;
        Result.fVal1 := lParam.fVal1 * 2;
    finally
        lParam.Free;
    end;
end;

My expectation:

function TTest.updateTest(param: TTestParam
): TTestParam;
begin
        Result := TTestParam.Create;
        Result.fVal1 := Param.fVal1 * 2;
end;

BTW – for output I a little wrapper on WebDispacher event:

var
  Aux: TJSONValue;
begin
  //remove [] element
    Aux := ResultVal;
    ResultVal := TJSONArray(Aux).Items[0];
    ResultVal.Owned := False;
    //TJSONArray(Aux).Remove(0);
    Aux.Free;

    Aux := ResultVal;
    ResultVal := TJSONObject(Aux).GetValue('fields');
    ResultVal.Owned := False;
    Aux.Free;

    Handled := true;
end;

Can I do maybe some reverted for input?