public void DeletePerson(int personInternalId)
        {
            var serviceInstanceQuery = ServiceInstances.Where(a => a.InternalParentId == personInternalId);

            if (serviceInstanceQuery.Any())
            {
                foreach (var serviceInstance in serviceInstanceQuery)
                {
                    DeleteServiceInstance(serviceInstance.InternalId);
                }
            }

            var personFollowUpQuery = PersonFollowUps.Where(a => a.InternalParentId == personInternalId);

            if (personFollowUpQuery.Any())
            {
                foreach (var personFollowUp in personFollowUpQuery)
                {
                    DeletePersonFollowUp(personFollowUp.InternalId);
                }
            }

            DeletePersonCustomValues(personInternalId);
            var personQuery = People.Where(a => a.InternalId == personInternalId);

            if (personQuery.Any())
            {
                People.RemoveRange(personQuery);
            }
        }
        public void DeletePersonFollowUp(int personFollowUpInternalId)
        {
            DeletePersonFollowUpCustomValues(personFollowUpInternalId);
            var personFollowUpQuery = PersonFollowUps.Where(a => a.InternalId == personFollowUpInternalId);

            if (personFollowUpQuery.Any())
            {
                PersonFollowUps.RemoveRange(personFollowUpQuery);
            }
        }