code: func newSliceIterator(rowIDs, columnIDs []uint64) *sliceIterator {
  	if len(columnIDs) != len(rowIDs) {
  		panic(fmt.Sprintf("pilosa.SliceIterator: pair length mismatch: %d != %d", len(rowIDs), len(columnIDs)))
  	}
  
  	return &sliceIterator{
  		rowIDs:    rowIDs,
  		columnIDs: columnIDs,
  
  		n: len(rowIDs),
  	}
  }
docs: // newSliceIterator returns an iterator to iterate over a set of row/column ID pairs.
  // Both slices MUST have an equal length. Otherwise the function will panic.