public static async Task <SearchResult> LoadPage(RisQueryParameter queryParam, int seitenNummer)
        {
            var risClient = new RisClient();
            var result    = await risClient.QueryAsync(queryParam, seitenNummer);

            return(result);
        }
        private static async Task<DocumentResult> LoadFromServiceAsync(string dokumentNummer)
        {
            var client = new RisClient();
            var result = await client.GetDocumentAsync(dokumentNummer);

            if (result.Succeeded)
            {
                return result;
            }

            return null;
        }