@staticmethod
def get_date(instance):
    """
        Guess date for instance based on the OS disk
        """
    for disk in instance['instance_view']['disks']:
        if disk['name'] == instance['storage_profile']['os_disk']['name']:
            try:
                return disk['statuses'][0]['time']
            except KeyError:
                break
    return instance['instance_view']['statuses'][0].get('time')
