public async Task Should_GetTimeSeries_Fundamentals_Annual()
        {
            var config = new ConfigurationBuilder()
                         .AddJsonFile("appsettings.json")
                         .Build();
            string    token  = config["TOKEN"];
            IEXClient client = new IEXClient(IEXBaseUrl.SandboxUrl, token);
            string    result = await client.GetTimeSeriesFundamentals("MSFT", "annual", new DateTime(2000, 1, 1), DateTime.Now);

            result.Should().NotBeNullOrEmpty();
        }