DRF:如何在定义序列化程序之前调用它(作为嵌套的序列化程序字段)？

from rest_framework import serializers

class NestedSerializer(serializers.ModelSerializer):
    # 定义嵌套的序列化程序字段
    nested_field = serializers.SerializerMethodField()

    def get_nested_field(self, obj):
        # 在这里调用其他序列化程序
        nested_obj = obj.nested_object
        serializer = OtherSerializer(nested_obj)
        return serializer.data

    class Meta:
        model = MyModel
        fields = ('nested_field', 'other_fields')