/// <summary>
        /// This method requires a user id in order to get all the grades of that user.
        /// </summary>
        /// <param name="id">The id</param>
        /// <returns>Returns a list of all grades of the selected user.</returns>
        public List <PrestationIndicator> getAverageGradeById(int id)
        {
            QueryStrings queryStrings            = new QueryStrings();
            List <PrestationIndicator> gradeList = queryStrings.getAverageGradeById(id);

            return(gradeList);
        }