SqlFunctions.DatePart equivalent in EF Core

for ef core 3.1 is little different solution, should cast argument first to SqlConstantExpression then pass its Value to SqlFragmentExpression constructor:

public static class DbFunctionExtensions
{
    public static int? DatePart(string type, DateTime? date) => throw new Exception();

    public static void ConfigureDbFunctions(this ModelBuilder modelBuilder)
    {
        var mi = typeof(DbFunctionExtensions).GetMethod(nameof(DatePart));

        modelBuilder.HasDbFunction(mi, b => b.HasTranslation(e =>
        {
            var ea = e.ToArray();
            var args = new[]
            {
                new SqlFragmentExpression((ea[0] as SqlConstantExpression).Value.ToString()),
                ea[1]
            };
            return SqlFunctionExpression.Create(nameof(DatePart), args, typeof(int?), null);
        }));
    }
}