public ICollection <VisitorViewModel> GetPagedVisitors(int page, int pageSize)
        {
            if (page <= 0)
            {
                throw new ArgumentOutOfRangeException(nameof(page));
            }
            if (pageSize <= 0)
            {
                throw new ArgumentOutOfRangeException(nameof(pageSize));
            }

            var lastVisitors = _visitorService.GetPagedVisitors(page, pageSize);
            var visitors     = _mapper.Map <ICollection <VisitorViewModel> >(lastVisitors);

            return(visitors);
        }