AutoMapper 5.0.0抛出CreateMap异常

我更新到AutoMapper 5.0.0和得到一个异常当AutoMapper试图创建地图

下面的示例抛出一个类似的异常{" System.Collections.Generic类型的表达式"。IEnumerable ' 1[DTOClass]'不能用于赋值给类型'System '。字符串"}

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("Start");
        Mapper.Initialize(cfg =>
        {
            cfg.CreateMap<string, IEnumerable<DTOClass>>().ConvertUsing(src =>
            {
                var response = JsonConvert.DeserializeObject<AnotherClass>(src);
                return response?.TestClasses == null ? null : Mapper.Map<IEnumerable<DTOClass>>(response.TestClasses);
            });
            cfg.CreateMap<TestClass, DTOClass>();
        });
        Console.WriteLine("Done");
    }
}

public class DTOClass
{
    public string Title { get; set; }
}
public class AnotherClass
{
    public TestClass[] TestClasses { get; set; }
}
public class TestClass
{
    public string Title { get; set; }
}