func (k *Key) InUint64(defaultVal uint64, candidates []uint64) uint64 {
	val := k.MustUint64()
	for _, cand := range candidates {
		if val == cand {
			return val
		}
	}
	return defaultVal
}
InUint64 always returns value without error,
it returns default value if error occurs or doesn't fit into candidates.
package ini
import (
	"bufio"
	"bytes"
	"errors"
	"fmt"
	"io"
	"os"
	"regexp"
	"runtime"
	"strconv"
	"strings"
	"sync"
	"time"
)
const (
	DEFAULT_SECTION = "DEFAULT"
	_DEPTH_VALUES = 99
	_VERSION = "1.7.0"
)
func Version() string {
	return _VERSION
}
var (
	LineBreak = "\n"
	varPattern = regexp.MustCompile(`%\(([^\)]+)\)s`)
	PrettyFormat = true
)
func init() {
	if runtime.GOOS == "windows" {
		LineBreak = "\r\n"
	}
}
func inSlice(str string, s []string) bool {
	for _, v := range s {
		if str == v {
			return true
		}
	}
	return false
}
type dataSource interface {
	ReadCloser() (io.ReadCloser, error)
}
type sourceFile struct {
	name string
}
func (s sourceFile) ReadCloser() (_ io.ReadCloser, err error) {
	return os.Open(s.name)
}
type bytesReadCloser struct {
	reader io.Reader
}
func (rc *bytesReadCloser) Read(p []byte) (n int, err error) {
	return rc.reader.Read(p)
}
func (rc *bytesReadCloser) Close() error {
	return nil
}
type sourceData struct {
	data []byte
}
func (s *sourceData) ReadCloser() (io.ReadCloser, error) {
	return &bytesReadCloser{bytes.NewReader(s.data)}, nil
}
type Key struct {
	s          *Section
	Comment    string
	name       string
	value      string
	isAutoIncr bool
}
func (k *Key) Name() string {
	return k.name
}
func (k *Key) Value() string {
	return k.value
}
func (k *Key) String() string {
	val := k.value
	if strings.Index(val, "%") == -1 {
		return val
	}
	for i := 0; i < _DEPTH_VALUES; i++ {
		vr := varPattern.FindString(val)
		if len(vr) == 0 {
			break
		}
		noption := strings.TrimLeft(vr, "%(")
		noption = strings.TrimRight(noption, ")s")
		nk, err := k.s.GetKey(noption)
		if err != nil {
			nk, _ = k.s.f.Section("").GetKey(noption)
		}
		val = strings.Replace(val, vr, nk.value, -1)
	}
	return val
}
func (k *Key) Validate(fn func(string) string) string {
	return fn(k.String())
}
func parseBool(str string) (value bool, err error) {
	switch str {
	case "1", "t", "T", "true", "TRUE", "True", "YES", "yes", "Yes", "ON", "on", "On":
		return true, nil
	case "0", "f", "F", "false", "FALSE", "False", "NO", "no", "No", "OFF", "off", "Off":
		return false, nil
	}
	return false, fmt.Errorf("parsing \"%s\": invalid syntax", str)
}
func (k *Key) Bool() (bool, error) {
	return parseBool(k.String())
}
func (k *Key) Float64() (float64, error) {
	return strconv.ParseFloat(k.String(), 64)
}
func (k *Key) Int() (int, error) {
	return strconv.Atoi(k.String())
}
func (k *Key) Int64() (int64, error) {
	return strconv.ParseInt(k.String(), 10, 64)
}
func (k *Key) Uint() (uint, error) {
	u, e := strconv.ParseUint(k.String(), 10, 64)
	return uint(u), e
}
func (k *Key) Uint64() (uint64, error) {
	return strconv.ParseUint(k.String(), 10, 64)
}
func (k *Key) Duration() (time.Duration, error) {
	return time.ParseDuration(k.String())
}
func (k *Key) TimeFormat(format string) (time.Time, error) {
	return time.Parse(format, k.String())
}
func (k *Key) Time() (time.Time, error) {
	return k.TimeFormat(time.RFC3339)
}
func (k *Key) MustString(defaultVal string) string {
	val := k.String()
	if len(val) == 0 {
		return defaultVal
	}
	return val
}
func (k *Key) MustBool(defaultVal ...bool) bool {
	val, err := k.Bool()
	if len(defaultVal) > 0 && err != nil {
		return defaultVal[0]
	}
	return val
}
func (k *Key) MustFloat64(defaultVal ...float64) float64 {
	val, err := k.Float64()
	if len(defaultVal) > 0 && err != nil {
		return defaultVal[0]
	}
	return val
}
func (k *Key) MustInt(defaultVal ...int) int {
	val, err := k.Int()
	if len(defaultVal) > 0 && err != nil {
		return defaultVal[0]
	}
	return val
}
func (k *Key) MustInt64(defaultVal ...int64) int64 {
	val, err := k.Int64()
	if len(defaultVal) > 0 && err != nil {
		return defaultVal[0]
	}
	return val
}
func (k *Key) MustUint(defaultVal ...uint) uint {
	val, err := k.Uint()
	if len(defaultVal) > 0 && err != nil {
		return defaultVal[0]
	}
	return val
}
func (k *Key) MustUint64(defaultVal ...uint64) uint64 {
	val, err := k.Uint64()
	if len(defaultVal) > 0 && err != nil {
		return defaultVal[0]
	}
	return val
}
func (k *Key) MustDuration(defaultVal ...time.Duration) time.Duration {
	val, err := k.Duration()
	if len(defaultVal) > 0 && err != nil {
		return defaultVal[0]
	}
	return val
}
func (k *Key) MustTimeFormat(format string, defaultVal ...time.Time) time.Time {
	val, err := k.TimeFormat(format)
	if len(defaultVal) > 0 && err != nil {
		return defaultVal[0]
	}
	return val
}
func (k *Key) MustTime(defaultVal ...time.Time) time.Time {
	return k.MustTimeFormat(time.RFC3339, defaultVal...)
}
func (k *Key) In(defaultVal string, candidates []string) string {
	val := k.String()
	for _, cand := range candidates {
		if val == cand {
			return val
		}
	}
	return defaultVal
}
func (k *Key) InFloat64(defaultVal float64, candidates []float64) float64 {
	val := k.MustFloat64()
	for _, cand := range candidates {
		if val == cand {
			return val
		}
	}
	return defaultVal
}
func (k *Key) InInt(defaultVal int, candidates []int) int {
	val := k.MustInt()
	for _, cand := range candidates {
		if val == cand {
			return val
		}
	}
	return defaultVal
}
func (k *Key) InInt64(defaultVal int64, candidates []int64) int64 {
	val := k.MustInt64()
	for _, cand := range candidates {
		if val == cand {
			return val
		}
	}
	return defaultVal
}
func (k *Key) InUint(defaultVal uint, candidates []uint) uint {
	val := k.MustUint()
	for _, cand := range candidates {
		if val == cand {
			return val
		}
	}
	return defaultVal
}