func (g *Glg) FailFunc(f func() string) error {
	if g.isModeEnable(FAIL) {
		return g.out(FAIL, "%s", f())
	}
	return nil
}
func (g *Glg) FailFunc(f func() string) error {
	if g.isModeEnable(FAIL) {
		return g.out(FAIL, "%s", f())
	}
	return nil
}
func ( g * Glg ) FailFunc ( f func ( ) string ) error { if g . isModeEnable ( FAIL ) { return g . out ( FAIL , " " , f ( ) ) } return nil }
// FailFunc outputs Fail level log returned from the function
FailFunc outputs Fail level log returned from the function