def create_instance(self, start_date=None):
if not start_date:
start_date = timezone.now()
provider_alias = str(uuid.uuid4())
identity = Identity.objects.filter(created_by=self.user).last()
if not identity:
identity = Identity(created_by=self.user, provider=self.provider)
identity.save()
instance_source = InstanceSource(provider=self.provider,
identifier=str(uuid.uuid4()),
created_by=self.user,
created_by_identity=identity)
instance_source.save()
instance = Instance(source=instance_source,
provider_alias=provider_alias,
created_by=self.user,
start_date=start_date)
instance.save()
self.create_instance_status_history(instance,
start_date=start_date,
status='active')
return instance
