How to use the @lhci/utils/src/build-context.js.getAncestorHashForBranch function in @lhci/utils

async function runLHCITarget(options) {
  if (!options.token) throw new Error('Must provide token for LHCI target');

  const api = new ApiClient({rootURL: options.serverBaseUrl, extraHeaders: options.extraHeaders});

  const project = await api.findProjectByToken(options.token);
  if (!project) {
    throw new Error('Could not find active project with provided token');
  }

  const hash = getCurrentHash();
  const branch = getCurrentBranch();
  const ancestorHash =
    branch === 'master' ? getAncestorHashForMaster() : getAncestorHashForBranch();

  const build = await api.createBuild({
    projectId: project.id,
    lifecycle: 'unsealed',
    hash,
    branch,
    ancestorHash,
    commitMessage: getCommitMessage(hash),
    author: getAuthor(hash),
    avatarUrl: getAvatarUrl(hash),
    externalBuildUrl: getExternalBuildUrl(),
    runAt: new Date().toISOString(),
    committedAt: getCommitTime(hash),
    ancestorCommittedAt: ancestorHash ? getCommitTime(ancestorHash) : undefined,
  });