How to specify nested attr (e.g., enclosure.url) as required?

[arnab]

I want to specify enclosure.url as a required property for episodes. How can I do that? If I specify:

    const options = {
      required: {
        episodes: ["title", "pubDate", "enclosure.url"],
      },
    };

It fails with Error: One or more required values are missing from feed.

How can I specify nested attributes such as enclosure.url as required?