public async Task AddFile(string description, byte[] file)
{
if (string.IsNullOrWhiteSpace(description))
{
Console.WriteLine("bad argument");
throw new ArgumentNullException(nameof(description));
}
if (file == null)
{
throw new ArgumentNullException(nameof(file));
}
Console.WriteLine("repository");
await _exerciseRepository.AddFile(description, file);
}