wagtail如何在ListBlock中序列化RichText字段

from wagtail.core.blocks import RichTextBlock, ListBlock
from wagtail.api import APIField

class RichTextListBlock(ListBlock):
    def __init__(self, **kwargs):
        super().__init__(RichTextBlock(), **kwargs)

class MyPage(Page):
    content = StreamField([
        ('rich_text_list', RichTextListBlock()),
    ])

class MyPage(Page):
    content = StreamField([
        ('rich_text_list', RichTextListBlock()),
    ])

    api_fields = [
        APIField('content'),
    ]