code: func (s *ChecksService) ListCheckRunsForRef(ctx context.Context, owner, repo, ref string, opt *ListCheckRunsOptions) (*ListCheckRunsResults, *Response, error) {
  	u := fmt.Sprintf("repos/%v/%v/commits/%v/check-runs", owner, repo, url.QueryEscape(ref))
  	u, err := addOptions(u, opt)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	req, err := s.client.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	req.Header.Set("Accept", mediaTypeCheckRunsPreview)
  
  	var checkRunResults *ListCheckRunsResults
  	resp, err := s.client.Do(ctx, req, &checkRunResults)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return checkRunResults, resp, nil
  }
docs: // ListCheckRunsForRef lists check runs for a specific ref.
  //
  // GitHub API docs: https://developer.github.com/v3/checks/runs/#list-check-runs-for-a-specific-ref