:param data: string data to be parsed.
        :return: Returns an STSElement.
        """
        try:
            return cls(root_name, cElementTree.fromstring(data))
        except _ETREE_EXCEPTIONS as error:
            raise InvalidXMLError(
                '"{}" XML is not parsable. Message: {}'.format(
                    root_name, error.message
                )
            )

            if response.status != 200:
                message = "Credential refresh failed, response: %s"
                raise CredentialRetrievalError(
                    provider=method,
                    error_msg=message % response.status,
                )

            creds = json.loads(response.data)

            query = {}
            query['Action'] = 'AssumeRoleWithClientGrants'

              "scope": "openid"}

    url = authorize_url + "?" + urllib.parse.urlencode(params)
    return url


@app.route('/oauth2/callback')
def callback():
    error = request.args.get('error', '')
    if error:
        return "Error: " + error

    authorization_code = request.args.get('code')

    data = {'grant_type': 'authorization_code',
            'code': authorization_code, 'redirect_uri': callback_uri}