docs: def get_args():
      """
      request the arguments for running
      """
      ap = argparse.ArgumentParser(description="Create frames for a movie that can be compiled using ffmpeg")
      ap.add_argument("start", help="date string as start time")
      ap.add_argument("end", help="date string as end time")
      ap.add_argument("step", type=float, help="fraction of a day to step by")
      ap.add_argument("--config", help="path to a config file", default="config.json")
      return ap.parse_args()