public string Filter([FromUri] string action, [FromBody] object value)
        {
            ResultObject resultt = new ResultObject();

            try
            {
                if (value != null)
                {
                    if ("filter".Equals(action))
                    {
                        try
                        {
                            var filterObject = JsonConvert.DeserializeObject <ExamFilterModel>(value.ToString());
                            return(JsonConvert.SerializeObject(services.Filter(filterObject), Formatting.Indented, new JsonSerializerSettings
                            {
                                ReferenceLoopHandling = ReferenceLoopHandling.Ignore
                            }));
                        }
                        catch (Exception ex)
                        {
                            return("Object fillter not convert valid");
                        }
                    }
                }
                if ("getfilter".Equals(action))
                {
                    return(JsonConvert.SerializeObject(services.listFilters()));
                }

                var result = services.GetAll().ToList();

                return(JsonConvert.SerializeObject(result, Formatting.Indented, new JsonSerializerSettings
                {
                    ReferenceLoopHandling = ReferenceLoopHandling.Ignore
                }));
            }
            catch (Exception e)
            {
                resultt.Message = "EXCEPTION: " + e.Message + "Stack: " + e.StackTrace;
                return(JsonConvert.SerializeObject(resultt));
            }
        }