django/tests/admin_scripts/app_raising_messages/models.py

from django.core import checks
from django.db import models


class ModelRaisingMessages(models.Model):
    @classmethod
    def check(self, **kwargs):
        return [
            checks.Warning('First warning', hint='Hint', obj='obj'),
            checks.Warning('Second warning', obj='a'),
            checks.Error('An error', hint='Error hint'),
        ]