private validateAssertionConditions(assertion: XmlParent): void {
        const conditions = assertion.getElementsByTagNameNS('urn:oasis:names:tc:SAML:2.0:assertion', 'Conditions')[0];
        if (conditions && !this.validateNotBeforeNotOnOrAfterAssertions(conditions)) {
            throw new Error('NotBefore / NotOnOrAfter assertion failed');
        }