如何在Django的序列化字段中更改布尔字段以显示类似Up = true或Down = False的值

from rest_framework import serializers

class CustomSerializer(serializers.Serializer):
    up = serializers.BooleanField()
    down = serializers.BooleanField()

    def to_representation(self, instance):
        representation = super().to_representation(instance)
        representation['up'] = 'Up = true' if representation['up'] else 'Up = false'
        representation['down'] = 'Down = true' if representation['down'] else 'Down = false'
        return representation

from rest_framework.views import APIView
from rest_framework.response import Response

class MyView(APIView):
    def get(self, request):
        data = {'up': True, 'down': False}
        serializer = CustomSerializer(data)
        return Response(serializer.data)