如何使用管理页面上的RadioSelect在Wagtail中制作ManyToOne？

from django.db import models
from wagtail.admin.edit_handlers import FieldPanel

class Author(models.Model):
    name = models.CharField(max_length=100)

class Book(models.Model):
    title = models.CharField(max_length=100)
    author = models.ForeignKey(Author, on_delete=models.CASCADE)

    panels = [
        FieldPanel('title'),
        FieldPanel('author', widget=forms.RadioSelect),
    ]

from wagtail.core.models import Page
from wagtail.admin.edit_handlers import FieldPanel

class BookPage(Page):
    book = models.ForeignKey(Book, on_delete=models.CASCADE)

    content_panels = Page.content_panels + [
        FieldPanel('book__author', widget=forms.RadioSelect),
    ]