我的www.example.com中有一个字段models.py，它接受类中确定的选项：

from apps.users.constants import UserChoices

class User(models.Model):
    choices = models.CharField(max_length=10, blank=True, choices=UserChoices.choices(), default=UserChoices.PUBLIC_USER)

选择类如下所示：

from django.utils.translation import ugettext_lazy as _

class UserChoices:
    PRIVATE_USER = "private_user"
    PUBLIC_USER = "public_user"

    @classmethod
    def choices(cls):
        return (
            (cls.PRIVATE_USER, _("Private User")),
            (cls.PUBLIC_USER, _("Public User")),
        )

我的疑问是如何将这个UserChoices类继承到另一个选择类，以便用另一个选项扩展它。
我尝试了以下方法：

class ExtendedChoices(UserChoices):

    OTHER_CHOICE = "other_choice"

    @classmethod
    def choices(cls):
        return (
            UserChoices.choices(),
            (cls.OTHER_CHOICE, _("Other choice")),
        )

但它给了我一个迁移错误：

users.OtherModel.other_choice: (fields.E005) 'choices' must be an iterable containing (actual value, human readable name) tuples.

显然，这个例子被简化了，实际代码在原始类上有40多个选项，在扩展类中有20多个选项。