DRF: custom ordering on related serializers

Since Django 1.7, you can specify a queryset for prefetch_related. Using prefetch incurs just one additional database query instead of one per parent object with SerializerMethodField.

from rest_framework import viewsets
from django.db.models import Prefetch

class InstructorViewSet(viewsets.ModelViewSet):
    queryset = Instructor.objects.prefetch_related(Prefetch(
        'courses',
        queryset=Course.objects.order_by('dept', 'number')))

Since it is read only, wouldn't it be just as easy to use a serializer method for that field?

class InstructorSerializer(serializers.ModelSerializer):
    courses = serializers.SerializerMethodField()

    def get_courses(self, obj):
         ordered_queryset = <do your magic here>
         return CourseSerializer(ordered_queryset, many=True, context=self.context).data