code: def auto_delete_pr_branch(pr: PullRequestDetails) -> bool:
      
  
      open_pulls = list_open_pull_requests(pr.repo, base_branch=pr.branch_name)
      if any(open_pulls):
          log('Not deleting branch {!r}. It is used elsewhere.'.format(
              pr.branch_name))
          return False
  
      remote = pr.remote_repo
      if pr.is_on_fork():
          log('Not deleting branch {!r}. It belongs to a fork ({}/{}).'.format(
              pr.branch_name,
              pr.remote_repo.organization,
              pr.remote_repo.name))
          return False
  
      url = ("https://api.github.com/repos/{}/{}/git/refs/heads/{}"
             "?access_token={}".format(remote.organization,
                                       remote.name,
                                       pr.branch_name,
                                       remote.access_token))
      response = requests.delete(url)
  
      if response.status_code == 204:
          # Delete succeeded.
          log('Deleted branch {!r}.'.format(pr.branch_name))
          return True
  
      log('Delete failed. Code: {}. Content: {}.'.format(
          response.status_code, response.content))
      return False
docs: References:
          https://developer.github.com/v3/git/refs/#delete-a-reference