public SqlUnitOfWork(string connectionString)
 {
     if (connectionString == null)
     {
         throw new ArgumentNullException(nameof(connectionString));
     }
     _context = new AdoNetContext(connectionString, true);
 }
 public DepartmentRepository(AdoNetContext context)
 {
     _context = context ?? throw new ArgumentNullException(nameof(context));
 }