code: func (it *iterator4List) Begin() Row {
  	if it.li.NumChunks() == 0 {
  		return it.End()
  	}
  	chk := it.li.GetChunk(0)
  	row := chk.GetRow(0)
  	if chk.NumRows() == 1 {
  		it.chkCursor = 1
  		it.rowCursor = 0
  	} else {
  		it.chkCursor = 0
  		it.rowCursor = 1
  	}
  	return row
  }
docs: // Begin implements the Iterator interface.