code: func (sf *StreamFile) writeSheetEnd() error {
  	if sf.currentSheet == nil {
  		return NoCurrentSheetError
  	}
  	if err := sf.currentSheet.write(endSheetDataTag); err != nil {
  		return err
  	}
  	return sf.currentSheet.write(sf.sheetXmlSuffix[sf.currentSheet.index-1])
  }
docs: // writeSheetEnd will write the end of the Sheet's XML