private void GetUnsortedPersonsFromFiles(string[] filePaths)
        {
            foreach (string filePath in filePaths)
            {

                string course = Regex.Replace(Path.GetFileName(filePath), ".txt$", String.Empty);

                using (var reader = new StreamReader(filePath))
                {
                    var query = (from line in reader.AsEnumerable()
                                 let columns = line.Split(' ')
                                 select new UnsortedPerson
                                 {
                                     FirstName = columns[0],
                                     LastName = columns[1],
                                     Grade = columns[2],
                                     Course = course
                                 }).ToList();

                    unsortedPersonsList.AddRange(query);
                }
            }
        }