def encode_labelme_shape(point_list):
    """
    Encode the labelme shape (usually a list of points)
    Return a serializable object (usually a string) for json dumping
    """
    code = list()
    for point in point_list:
        assert len(point) == 2
        code.append('{:.6f}+{:.6f}'.format(point[0], point[1]))
    code = ','.join(code)
    return code