Database.SetInitializer<ApplicationDbContext>(null);
 // Database.SetInitializer(new MigrateDatabaseToLatestVersion<ApplicationDbContext, Configuration>());
 //ProjectObjectFactory.Container.GetInstance<IUnitOfWork>().ForceDatabaseInitialize();

// Database.SetInitializer<ApplicationDbContext>(null);
Database.SetInitializer(new MigrateDatabaseToLatestVersion<ApplicationDbContext, Configuration>());
ProjectObjectFactory.Container.GetInstance<IUnitOfWork>().ForceDatabaseInitialize();

public bool DoSomething(string id, string name, string favouriteColour)
{
    //if (id is null)
    //{
    //   throw new ArgumentNullException(nameof(id));
    //}
    
    ArgumentNullException.ThrowIfNull(id);
   //...
}

// Before
void Insert(string s) {
 if (s is null) {
   throw new ArgumentNullException(nameof(s));
 }
 ...
}

// After
void Insert(string s!) {
  ...
}

var comments = _dbContext.Comments.Where(x => x.ReplyId == null).Include(x => x.Children).ToList();

{ "Value": null }

    public class StringJsonConverter : JsonConverter<byte?>
    {
        public override byte? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            return reader.TokenType switch
            {
                JsonTokenType.Number => reader.GetByte(),
                JsonTokenType.Null => null,
                JsonTokenType.String =>
                    byte.TryParse(reader.GetString(), NumberStyles.Number, CultureInfo.InvariantCulture, out var parsed) ? parsed : (byte?)null,
                _ => throw new ArgumentOutOfRangeException(nameof(reader), reader.TokenType, "Cannot parse unexpected JSON token type.")
            };
        }

        public override void Write(Utf8JsonWriter writer, byte? value, JsonSerializerOptions options)
        {
            if (value.HasValue)
            {
                writer.WriteNumberValue(value.Value);
            }
            else
            {
                writer.WriteNullValue();
            }
        }
    }

An unexpected error happened; package X-editable has no version null.