Since google_appengine isn't part of the uploaded trunk/app, there is no reason
why it couldn't be in a thirdparty directory, alongside mocker.
from django.core.management.base import NoArgsCommand
class Command(NoArgsCommand):
help = "Validates all installed models."
requires_model_validation = False
def handle_noargs(self, **options):
self.validate(display_num_errors=True)