DRF：向Serializer添加“url”字段会导致在浏览API时出现“无法解析URL”错误

I'm new to Django REST Framework and have been frustrated for a while by something that seems very simple. I have a Serializer that I'm trying to switch to a HyperLinkedModelSerializer. I went through the DRF quickstart guide, and I think my Serializer and Viewset are very similar to the examples in there:I'm new to Django REST Framework and have been