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