digits[i]++
	} else {
		// digits is all zeros
		digits[0] = '1'
		digits = append(digits, '0')
	}
	return string(digits)
}

// decDecimal returns the decimal string decremented by 1, or the empty string
// if the decimal is all zeroes.
func decDecimal(decimal string) string {
	// Scan right to left turning 0s to 9s until you find a digit to decrement.
	digits := []byte(decimal)
	i := len(digits) - 1

		return -1
	} else {
		return +1
	}
}

// DecInt returns the decimal string decremented by 1, or the empty string
// if the decimal is all zeroes.
// (Copied from golang.org/x/mod/module's decDecimal.)
func DecInt(decimal string) string {
	// Scan right to left turning 0s to 9s until you find a digit to decrement.
	digits := []byte(decimal)
	i := len(digits) - 1
	for ; i >= 0 && digits[i] == '0'; i-- {