public bool DeleteTimeSlotOfDoctor(string userid, string slotId)
        {
            var _ts = repository.GetSpecificSlotOfDoctor(userid, slotId);

            if (_ts != null)
            {
                return(repository.DeleteTimeSlotOfDoctor(userid, slotId));
            }
            else
            {
                throw new TimeSlotNotFoundException("No Such Time Slot Exists");
            }
        }