users = User.objects.all()
   for user in users:
       user.comments.all()[:10]

User.objects.all().prefetch_related('comments', limit=10)

User.objects.all().prefetch_related(
    Prefetch('msg_sent', queryset=UserMsg.objects.order_by('-created')[:10]))

AssertionError: Cannot filter a query once a slice has been taken.

from datetime import datetime, timedelta
timelimit = datetime.now() - timedelta(days=365)

User.objects.all().prefetch_related(
    Prefetch('msg_sent', queryset=UserMsg.objects.filter(created__gte=timelimit)))