from django.contrib import admin
from django.urls import path
from blog.sitemaps import PostSitemap, StaticViewSitemap
from django.contrib.sitemaps.views import sitemap

sitemaps =  {
    'Posts' : PostSitemap,
}

url_patterns =  [
        path('admin/', admin.site.urls),
        ...
        path('sitemap.xml',
                   sitemap,
                   {'sitemaps': sitemaps}, name='django.contrib.sitemaps.views.sitemap')
]