private async void saveModify(RegistrationManager.DayOfWeek dayOfWeek)
        {
            //l'errore risiede nel fatto che va modificato il parse object, non il reg manager! Altrimenti nasce una nuova copia i oggetto!

            DayTimespan newspan = new DayTimespan(openingAMTimePicker.Time, closingAMTimePicker.Time,
                            openingPMTimePicker.Time, closingPMTimePicker.Time, mChecked);

            ParseObject account = RegistrationManager.getInstance().currAccount;

            IDictionary<string, string> dict = account.Get<IDictionary<string, string>>("dictionary");

            if (dict.ContainsKey(dayOfWeek.ToString()))
            {
                dict.Remove(dayOfWeek.ToString());
                string obj = Newtonsoft.Json.JsonConvert.SerializeObject(newspan);
                dict.Add(dayOfWeek.ToString(), obj);
                account["dictionary"] = dict;
                await account.SaveAsync();
                return;
            }

            RegistrationManager.getInstance().changeDayTime(dayOfWeek.ToString(), new DayTimespan(openingAMTimePicker.Time, closingAMTimePicker.Time,
                            openingPMTimePicker.Time, closingPMTimePicker.Time, mChecked));
            await RegistrationManager.getInstance().getParseObject().SaveAsync();
        }
        /*Modifies a timespan for a certain day of week*/
        public Boolean changeDayTime(string day, DayTimespan time)
        {
            if (daytime.ContainsKey(day))
            {
                daytime.Remove(day);

                //usare serializzazione json
                string obj = Newtonsoft.Json.JsonConvert.SerializeObject(time);
                daytime.Add(day, obj);
                return true;
            }
            return false;
        }
        /*Adds a Daytimespan to a specific day of the week. if the day already exixts, returns false*/
        public Boolean addDayTime(string day , DayTimespan time)
        {
            if (daytime.ContainsKey(day))
            {
                return false;
            }

            //Json Serialization

            string obj = Newtonsoft.Json.JsonConvert.SerializeObject(time);

            daytime.Add(day, obj);
            return true;
        }