Enter apex range of cells of excel sheet

General
1

This routine generated by a macro excel tells me error in Xojo.
Why?
dim excel As New ExcelApplication
dim book As ExcelWorkbook
book = excel.Workbooks.Open(“C:\FileProva.xls”)

For Each excel.cella in excel.ActiveSheet.Range(“a1:a5”)
excel.cella = “’” + excel.cella.Value
Next excel.cella