Returns the size in bytes if `path` is a file,
        or the size of all files in `path` if it's a directory.
        Analogous to `du -s`.

def get_size(path):
    """ Returns the size in bytes if `path` is a file,
        or the size of all files in `path` if it's a directory.
        Analogous to `du -s`.
    """
    if os.path.isfile(path):
        return os.path.getsize(path)
    return sum(get_size(os.path.join(path, f)) for f in os.listdir(path))