django1/django/contrib/auth/apps.py

from django.apps import AppConfig
from django.core import checks
from django.contrib.auth.checks import check_user_model

from django.utils.translation import ugettext_lazy as _


class AuthConfig(AppConfig):
    name = 'django.contrib.auth'
    verbose_name = _("authentication and authorization")

    def ready(self):
        checks.register('models')(check_user_model)