private async Task <IEnumerable <SelectListItem> > GetContactTypes()
        {
            logger.LogInformation("GetContactTypes called.");
            var contactTypes = await referenceDataApiClient.GetContactTypesAsync();

            Guard.Against.Null(contactTypes, nameof(contactTypes));

            var items = contactTypes
                        .Select(at => new SelectListItem()
            {
                Value = at.Name, Text = at.Name
            })
                        .ToList();

            var allItem = new SelectListItem()
            {
                Value = "", Text = "--Select--", Selected = true
            };

            items.Insert(0, allItem);

            return(items);
        }