def METHOD_NAME(comm_points, filename="comm_points.dat"):
    with open(os.path.join(data_dir, filename), "w") as w:
        lines = []
        for i, p in enumerate(comm_points):
            lines.append("%d %5.2f %5.2f %5.2f" % ((i + 1,) + tuple(p)))
        w.write("\n".join(lines))