code: func (s *RepositoriesService) GetCombinedStatus(ctx context.Context, owner, repo, ref string, opt *ListOptions) (*CombinedStatus, *Response, error) {
  	u := fmt.Sprintf("repos/%v/%v/commits/%v/status", 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
  	}
  
  	status := new(CombinedStatus)
  	resp, err := s.client.Do(ctx, req, status)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return status, resp, nil
  }
docs: // GetCombinedStatus returns the combined status of a repository at the specified
  // reference. ref can be a SHA, a branch name, or a tag name.
  //
  // GitHub API docs: https://developer.github.com/v3/repos/statuses/#get-the-combined-status-for-a-specific-ref