function main(sourceName = 'YOUR_NUMERIC_ORG_ID') {
  // [START securitycenter_list_findings_with_security_marks]
  // Imports the Google Cloud client library.
  const {SecurityCenterClient} = require('@google-cloud/security-center');

  // Creates a new client.
  const client = new SecurityCenterClient();
  //  sourceName is the full resource path of the source to search for
  //  findings.
  /*
   * TODO(developer): Uncomment the following lines
   */
  // const sourceName = `${parent}/sources/${sourceId}`;
  // where,
  // parent: must be in one of the following formats:
  //    `organizations/${organization_id}`
  //    `projects/${project_id}`
  //    `folders/${folder_id}`

  async function listFindingsWithSecurityMarks() {
    const [response] = await client.listFindings({
      // List findings across all sources.
      parent: sourceName,
      filter: 'NOT security_marks.marks.key_a="value_a"',
    });
    let count = 0;
    Array.from(response).forEach(result =>
      console.log(
        `${++count} ${result.finding.name} ${result.finding.resourceName}`
      )
    );
  }
  listFindingsWithSecurityMarks();
  // [END securitycenter_list_findings_with_security_marks]
}
Demonstrates listing findings by filtering on security marks.