code: func NewCells(options []interface{}) (Cells, error) {
  	var cells Cells
  	for _, o := range options {
  		switch m := o.(type) {
  		case metrics.CounterOpts:
  			cells = append(cells, counterCell(m))
  		case metrics.GaugeOpts:
  			cells = append(cells, gaugeCell(m))
  		case metrics.HistogramOpts:
  			cells = append(cells, histogramCell(m))
  		default:
  			return nil, fmt.Errorf("unknown option type: %t", o)
  		}
  	}
  	sort.Sort(cells)
  	return cells, nil
  }
docs: // NewCells transforms metrics options to cells that can be used for doc
  // generation.