public IEnumerable <IItemResult> Results(string actionKeyword, string search)
        {
            if (search == null)
            {
                throw new ArgumentNullException(nameof(search));
            }

            if (!_environmentHelper.IsEnvironmentVariable(search))
            {
                return(Enumerable.Empty <IItemResult>());
            }

            return(_queryEnvironmentVariable.Query(search));
        }