如何在自定义验证属性中获取模型实例

from django.db import models

class MyModel(models.Model):
    name = models.CharField(max_length=100)
    # 其他字段...

def validate_custom_attribute(value):
    try:
        instance = MyModel.objects.get(id=value)  # 通过ID获取模型实例
        # 进一步处理验证逻辑，例如检查模型实例的属性或方法
        if instance.name == "特定名称":
            raise ValidationError("名称无效")
    except MyModel.DoesNotExist:
        raise ValidationError("模型实例不存在")

class MyModelForm(forms.ModelForm):
    custom_attribute = forms.IntegerField(validators=[validate_custom_attribute])

    class Meta:
        model = MyModel
        fields = '__all__'