'Return a string containing the authorization token for the pod.'

@classmethod
def get_auth_token(cls, instance):

    token_path = instance.get('bearer_token_path', cls.AUTH_TOKEN_PATH)
    try:
        with open(token_path) as f:
            return f.read().strip()
    except IOError as e:
        log.error('Unable    to    read    token    from    {}:    {}'.format(token_path, e))
    return None
