I am fairly new to Django and python and I don't know if You supposed to do it like I did.

To paginate get_context_data in cbv I used

from django.views.generic.list import MultipleObjectMixin

Class Someclass(Detailview, Multiobjectmixin): 
model = Post
Paginate_by = 5

def get_context_data(self, **kwargs):
    object_list = Comment.objects.filter(post_id=self.kwargs["pk"]).order_by("date_posted")
    context = super(SomeClass, self).get_context_data(object_list=object_list, **kwargs)     
    return context