how to use values in clause in django query set code example

Example 1: pass in queryset as filter django

users = UserClasses.objects.filter(class_id=data['class_id'])
user_details = User.objects.filter(id__in=users.values_list('id', flat=True))

Example 2: django queryset count

# Returns the total number of entries in the database.
Entry.objects.count()

# Returns the number of entries whose headline contains 'Lennon'
Entry.objects.filter(headline__contains='Lennon').count()