The GetCellFormula in same cell not working properly

[raochq]

when I copy a sheet to another file. The formula in same cell may not correct.

package main

import (
	"github.com/360EntSecGroup-Skylar/excelize/v2"
)

func main() {
	sheetName := "Sheet1"
	f1, _ := excelize.OpenFile("input.xlsx")
	f2 := excelize.NewFile()
	rows, _ := f1.GetRows(sheetName)
	for r, row := range rows {
		for c, s := range row {
			axis, _ := excelize.CoordinatesToCellName(c+1, r+1)
			formula, _ := f1.GetCellFormula(sheetName, axis)
			if formula != "" {
				f2.SetCellFormula(sheetName, axis, formula)
			} else {
				f2.SetCellValue(sheetName, axis, s)
			}
		}
	}
	f2.SaveAs("output.xlsx")
}

input.xlsx