bolthelper.go
func Open(path string, mode os.FileMode, options *bolt.Options) (DB, error) {
	db, err := bolt.Open(path, mode, options)
	return DB{db}, errorsp.WithStacks(err)
}
func Open(path string, mode os.FileMode, options *bolt.Options) (DB, error) {
	db, err := bolt.Open(path, mode, options)
	return DB{db}, errorsp.WithStacks(err)
}
// Open creates and opens a database at the given path. If the file does
// not exist then it will be created automatically. Passing in nil options
// will cause Bolt to open the database with the default options.