'Receive new token if user need to update old token
:return: new token that can be used for authentication'

def refresh_token(self):

    LOG.debug('Requesting    the    new    token    with    trust    %s', self.trust_id)
    if (self.trustee_client is None):
        self.trustee_client = self._refresh_trustee_client()
    try:
        return self.trustee_client.session.get_token()
    except ka_exceptions.Unauthorized:
        self.trustee_client = self._refresh_trustee_client()
        return self.trustee_client.session.get_token()
