putCellValue() numerical params not clear

Assuming I have a code `putCellValue(5, 6, data):`

After trial and error, I found out that the 1st and 2nd parameters, 5 and 6, respectively, means that the data will be put in 6th row and 7th column (G6).

I don't find it a bug but I hope you could have wrote an API telling us that the numbering is based on array indexes (start with 0).