def save_list(trajs, filename):
        """Saves a set of trajectories into a text file.

        Parameters
        ----------

        trajs : list
          List of trajectories to be saved.

        filename : str
          Path of the text file that will store the trajectories data.
        """
        N = len(trajs)
        arr = np.hstack([np.array(list(t.txy(tms=True))) for t in trajs])
        np.savetxt(
            filename,
            arr,
            fmt="%d",
            delimiter="\t",
            header="\t".join(N * ["t(ms)", "x", "y"]),
        )
Saves a set of trajectories into a text file.

        Parameters
        ----------

        trajs : list
          List of trajectories to be saved.

        filename : str
          Path of the text file that will store the trajectories data.
        
moviepy/video/tools/interpolators.py