def get_volume(self, id):
        """
        return volume information if the argument is an id or a path
        """
        # If the id is actually a path
        if exists(id):
            with open(id) as file:
                size = os.lseek(file.fileno(), 0, os.SEEK_END)
            return {'path': id, 'size': size}
        return self.volume.get(id)