dates semantics in RSS

I'm reading the documentation of feedparser.开发者_StackOverflow社区

It describes 4 attributes related to date

1. published
2. updated
3. created
4. expired

What do these attributes mean in relation to RSS specification? It describes only pubDate

thank you

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Feedparser covers several syndication formats, for example Atom syndication format (RFC 4287). That is why you see a mis-match with the (relatively old) RSS standard.

The documentation for feedparser has details about the semantics and where in the feed it picks up the values:

Published:

The date this entry was first published

Updated:

The date this entry was last updated

Created:

The date this entry was first created (drafted)

Expired:

The date this entry is set to expire [...] This element is rare.