code: func (s *RepositoriesService) ListKeys(ctx context.Context, owner string, repo string, opt *ListOptions) ([]*Key, *Response, error) {
  	u := fmt.Sprintf("repos/%v/%v/keys", owner, repo)
  	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
  	}
  
  	var keys []*Key
  	resp, err := s.client.Do(ctx, req, &keys)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return keys, resp, nil
  }
docs: // The Key type is defined in users_keys.go
  // ListKeys lists the deploy keys for a repository.
  //
  // GitHub API docs: https://developer.github.com/v3/repos/keys/#list