code: func (r *Client) DeleteDashboard(slug string) (StatusMessage, error) {
  	var (
  		isBoardFromDB bool
  		raw           []byte
  		reply         StatusMessage
  		err           error
  	)
  	if slug, isBoardFromDB = cleanPrefix(slug); !isBoardFromDB {
  		return StatusMessage{}, errors.New("only database dashboards (with 'db/' prefix in a slug) can be removed")
  	}
  	if raw, _, err = r.delete(fmt.Sprintf("api/dashboards/db/%s", slug)); err != nil {
  		return StatusMessage{}, err
  	}
  	err = json.Unmarshal(raw, &reply)
  	return reply, err
  }
docs: // DeleteDashboard deletes dashboard that selected by slug string.
  // Grafana only can delete a dashboard in a database. File dashboards
  // may be only loaded with HTTP API but not deteled.