code: def open_movie(self, filename, framerate=24):
          
          if isinstance(vtki.FIGURE_PATH, str) and not os.path.isabs(filename):
              filename = os.path.join(vtki.FIGURE_PATH, filename)
          self.mwriter = imageio.get_writer(filename, fps=framerate)
docs: Establishes a connection to the ffmpeg writer
  
          Parameters
          ----------
          filename : str
              Filename of the movie to open.  Filename should end in mp4,
              but other filetypes may be supported.  See "imagio.get_writer"
  
          framerate : int, optional
              Frames per second.