file/info.go
func IsDir(name string) (bool, error) {
	i, err := NewInfo(name)
	if err != nil {
		return false, err
	}
	return i.IsDir(), nil
}
func IsDir(name string) (bool, error) {
	i, err := NewInfo(name)
	if err != nil {
		return false, err
	}
	return i.IsDir(), nil
}
// * * *
// IsDir reports whether if the named file is a directory.