You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: parseduration.go
    path of file: ./repos/rclone/fs
    
    the code of the file until where you have to start completion: package fs

import (
	"fmt"
	"math"
	"strconv"
	"strings"
	"time"
)

// Duration is a time.Duration with some more parsing options
type Duration time.Duration

// DurationOff is the default value for flags which can be turned off
const DurationOff = Duration((1 << 63) - 1)

// Turn Duration into a string
func (d Duration) String() string {
	if d == DurationOff {
		return "off"
	}
	for i := len(ageS
    
func parseDurationSuffixes(age string) (time.Duration, error) {
	var period float64

	for _, ageSuffix := range ageSuffixes {
		if strings.HasSuffix(age, ageSuffix.Suffix) {
			numberString := age[:len(age)-len(ageSuffix.Suffix)]
			var err error
			period, err = strconv.ParseFloat(numberString, 64)
			if err != nil {
				return time.Duration(0), err
			}
			period *= float64(ageSuffix.Multiplier)
			break
		}
	}

	return time.Duration(period), nil
}