Sitemap urlset http or https [duplicate]

I am a Static User I write my all pages and sitemap with pure html css code, I have a question that in sitemap I am using http xmlns in order to make my sitemaps so is it allowed to add https or http is better that’s why all are using it.

<urlset xmlns="" xmlns:xsi="" xsi:schemaLocation=""> 

So in the above I would like to ask that is it allowed to use https xmlns?