Checks if the Logout Request received is valid
        :param request_data: Request Data
        :type request_data: dict

        :param raise_exceptions: Whether to return false on failure or raise an exception
        :type raise_exceptions: Boolean

        :return: If the Logout Request is or not valid
        :rtype: boolean

def is_valid(self, request_data, raise_exceptions=False):
        """
        Checks if the Logout Request received is valid
        :param request_data: Request Data
        :type request_data: dict

        :param raise_exceptions: Whether to return false on failure or raise an exception
        :type raise_exceptions: Boolean

        :return: If the Logout Request is or not valid
        :rtype: boolean
        """
        self.__error = None
        try:
            root = OneLogin_Saml2_XML.to_etree(self.__logout_request)

            idp_data = self.__settings.get_idp_data()
            idp_entity_id = idp_data['entityId']

            get_data = ('get_data' in request_data and request_data['get_data']) or dict()

            if self.__settings.is_strict():
                res = OneLogin_Saml2_XML.validate_xml(root, 'saml-schema-protocol-2.0.xsd', self.__settings.is_debug_active())
                if isinstance(res, str):
                    raise OneLogin_Saml2_ValidationError(
                        'Invalid SAML Logout Request. Not match the saml-schema-protocol-2.0.xsd',
                        OneLogin_Saml2_ValidationError.INVALID_XML_FORMAT
                    )

                security = self.__settings.get_security_data()

                current_url = OneLogin_Saml2_Utils.get_self_url_no_query(request_data)

                # Check NotOnOrAfter
                if root.get('NotOnOrAfter', None):
                    na = OneLogin_Saml2_Utils.parse_SAML_to_time(root.get('NotOnOrAfter'))
                    if na <= OneLogin_Saml2_Utils.now():
                        raise OneLogin_Saml2_ValidationError(
                            'Could not validate timestamp: expired. Check system clock.)',
                            OneLogin_Saml2_ValidationError.RESPONSE_EXPIRED
                        )

                # Check destination
                if root.get('Destination', None):
                    destination = root.get('Destination')
                    if destination != '':
                        if current_url not in destination:
                            raise OneLogin_Saml2_ValidationError(
                                'The LogoutRequest was received at '
                                '%(currentURL)s instead of %(destination)s' %
                                {
                                    'currentURL': current_url,
                                    'destination': destination,
                                },
                                OneLogin_Saml2_ValidationError.WRONG_DESTINATION
                            )

                # Check issuer
                issuer = OneLogin_Saml2_Logout_Request.get_issuer(root)
                if issuer is not None and issuer != idp_entity_id:
                    raise OneLogin_Saml2_ValidationError(
                        'Invalid issuer in the Logout Request (expected %(idpEntityId)s, got %(issuer)s)' %
                        {
                            'idpEntityId': idp_entity_id,
                            'issuer': issuer
                        },
                        OneLogin_Saml2_ValidationError.WRONG_ISSUER
                    )

                if security['wantMessagesSigned']:
                    if 'Signature' not in get_data:
                        raise OneLogin_Saml2_ValidationError(
                            'The Message of the Logout Request is not signed and the SP require it',
                            OneLogin_Saml2_ValidationError.NO_SIGNED_MESSAGE
                        )

            return True
        except Exception as err:
            # pylint: disable=R0801
            self.__error = str(err)
            debug = self.__settings.is_debug_active()
            if debug:
                print(err)
            if raise_exceptions:
                raise
            return False