code: func (s *PullRequestsService) Get(ctx context.Context, owner string, repo string, number int) (*PullRequest, *Response, error) {
  	u := fmt.Sprintf("repos/%v/%v/pulls/%d", owner, repo, number)
  	req, err := s.client.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	// TODO: remove custom Accept header when this API fully launches.
  	acceptHeaders := []string{mediaTypeLabelDescriptionSearchPreview, mediaTypeLockReasonPreview, mediaTypeDraftPreview}
  	req.Header.Set("Accept", strings.Join(acceptHeaders, ", "))
  
  	pull := new(PullRequest)
  	resp, err := s.client.Do(ctx, req, pull)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return pull, resp, nil
  }
docs: // Get a single pull request.
  //
  // GitHub API docs: https://developer.github.com/v3/pulls/#get-a-single-pull-request