Remove <lastmod>

[BenSotty]

Hi there 👋,

For some pages I do not know when they have been modified.
So, for those pages I don't want the <lastmod> to appear in the sitemap.xml.
But for a Spatie\Sitemap\Tags\Url, setLastModificationDate expects a DateTimeInterface as argument.
Thus: $url->setLastModificationDate(null); breaks.
Is there a way to remove <lastmod> from the sitemap ?

Thanks a lot for your help.
Thanks a lot for the tool :)

[ideea]

any update on this one? :)