如何在一个模型字段中处理2个字段类型？

from django.db import models
from django.core.serializers.json import DjangoJSONEncoder
import json

class MultiTypeField(models.Field):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

    def from_db_value(self, value, expression, connection):
        if value is None:
            return value
        return json.loads(value, object_hook=self.decode_object)

    def to_python(self, value):
        if isinstance(value, dict):
            return value
        if value is None:
            return value
        return json.loads(value, object_hook=self.decode_object)

    def get_prep_value(self, value):
        if value is None:
            return value
        return json.dumps(value, cls=DjangoJSONEncoder)

    def decode_object(self, obj):
        # 这里可以根据实际需求解码对象
        return obj

class MyModel(models.Model):
    name = models.CharField(max_length=100)
    value = MultiTypeField()

# 使用示例
my_instance = MyModel(name="Test", value={"type": "int", "value": 123})
my_instance.save()

# 读取示例
loaded_instance = MyModel.objects.get(name="Test")
print(loaded_instance.value)  # 输出: {'type': 'int', 'value': 123}