/// <summary>
        /// Adds the prescription to the AllPrescriptions property or refreshes it if it's a new group.
        /// </summary>
        /// <param name="item"></param>
        public async void AddPrescriptionToCollection(Prescription item)
        {
            bool isSessionPresent = AllPrescriptions.Any(p => p.TimeStamp == item.Schedule);

            if (isSessionPresent)
            {
                AllPrescriptions.Single(grp => grp.TimeStamp == item.Schedule).Prescriptions.Add(item);
            }
            else
            {
                await RefreshDataAsync();
            }
        }
        /// <summary>
        /// Removes the prescription.
        /// </summary>
        /// <param name="selectedItem"></param>
        public async void DeletePrescription(object selectedItem)
        {
            try
            {
                Prescription item = selectedItem as Prescription;
                await imsSvc.DeletePrescriptionAsync(item);

                var group = AllPrescriptions.Single(grp => grp.TimeStamp == item.Schedule);
                if (group.Prescriptions.Count > 1)
                {
                    AllPrescriptions.Single(grp => grp.TimeStamp == item.Schedule).Prescriptions.Remove(item);
                    Prescriptions.Single(grp => grp.TimeStamp == item.Schedule).Prescriptions.Remove(item);
                }
                else
                {
                    AllPrescriptions.Remove(group);
                    Prescriptions.Remove(group);
                }
            }
            catch (Exception e)
            {
                MessengerInstance.Send(new ExceptionDialogMessage(e));
            }
        }