How to use the kobo.hub.models.Worker.objects function in kobo

def setUp(self):
        self._fixture_teardown()
        self.worker1 = Worker.objects.create(
            worker_key='worker-1',
            name='worker-1',
        )

        self.worker2 = Worker.objects.create(
            worker_key='worker-2',
            name='worker-2',
        )

        self.client = django.test.Client()

def test_list_workers_enabled(self):
        Worker.objects.create(
            worker_key='enabled-worker',
            name='enabled-worker',
            enabled=True,
        )

        Worker.objects.create(
            worker_key='disabled-worker',
            name='disabled-worker',
            enabled=False,
        )

        worker_list = client.list_workers(_make_request(), True)
        self.assertEqual(len(worker_list), 1)
        self.assertEqual(worker_list[0], 'enabled-worker')

Task.objects.create(
            worker=worker1,
            arch=self._arch,
            channel=self._channel,
            owner=self._user,
            method='DummyTask',
            state=TASK_STATES['OPEN'],
            weight=100
        )

        worker1.save()

        worker2 = Worker.objects.create(worker_key='worker-2', name='Worker 2', enabled=True)

        workers = Worker.objects.ready()
        self.assertEquals(len(workers), 1)
        self.assertEquals(workers[0].id, worker2.id)

def test_enabled(self):
        Worker.objects.create(worker_key='worker-disabled', name='Worker disabled', enabled=False)
        worker = Worker.objects.create(worker_key='worker-enabled', name='Worker enabled', enabled=True)

        workers = Worker.objects.enabled()
        self.assertEquals(len(workers), 1)
        self.assertEquals(workers[0].id, worker.id)

def test_assigned_tasks(self):
        worker = Worker.objects.create(worker_key='worker', name='Worker')

        Task.objects.create(
            worker=worker,
            arch=self._arch,
            channel=self._channel,
            owner=self._user,
            method='DummyTask',
            state=TASK_STATES['ASSIGNED'],
        )

        Task.objects.create(
            worker=worker,
            arch=self._arch,
            channel=self._channel,
            owner=self._user,
            method='DummyTask',

def save(self, *args, **kwargs):
        # precompute task count, current load and ready
        tasks = Task.objects.opened().filter(worker=self)
        self.task_count = tasks.count()
        self.current_load = sum(( task.weight for task in tasks if not task.waiting ))
        self.ready = self.enabled and (self.current_load < self.max_load and self.task_count < 3*self.max_load)

        while not self.worker_key:
            # if worker_key is empty, generate a new one
            key = random_string(64)
            if Worker.objects.filter(worker_key=key).count() == 0:
                self.worker_key = key
        super(self.__class__, self).save(*args, **kwargs)

from django.conf.urls import url
from django.utils.translation import ugettext_lazy as _
from kobo.django.views.generic import ExtraListView, ExtraDetailView
from kobo.hub.models import Worker


urlpatterns = [
    url(r"^$", ExtraListView.as_view(
        queryset=Worker.objects.order_by("name"),
        template_name="worker/list.html",
        context_object_name="worker_list",
        title = _("Workers"),
    ), name="worker/list"),
    url(r"^(?P\d+)/$", ExtraDetailView.as_view(
        queryset=Worker.objects.select_related(),
        template_name="worker/detail.html",
        context_object_name="worker",
        title=_("Worker detail"),
    ), name="worker/detail"),
]