'Schedules a special task on a host if the task is not already scheduled.'

@classmethod
def schedule_special_task(cls, host, task):

    existing_tasks = SpecialTask.objects.filter(host__id=host.id, task=task, is_active=False, is_complete=False)
    if existing_tasks:
        return existing_tasks[0]
    special_task = SpecialTask(host=host, task=task, requested_by=User.current_user())
    special_task.save()
    return special_task
