如何显示来自UniqueConstraint的用户友好的错误消息?

class MyModel(models.Model):
    start_date = models.DateField(
        verbose_name='Start date',
        blank=False,
        null=False,
        unique=True,
        error_messages={'unique':"This start date has already been registered."}
    )

但是,当我保存一个违反此规则的模型实例时 UniqueConstraint 我得到一份工作 IntegrityError

duplicate key value violates unique constraint "myapp_mymodel_start_date_af14e233_uniq"
DETAIL:  Key (end_date)=(2021-10-21) already exists.

如何输出“干净”的用户友好错误消息?