Downloads the video.

        If self.client.cache_enabled is True, then the disk cache is used.

        Returns:
            The path where the video has been saved.

        Raises:
            DownloadError: If the video cannot be downloaded.

def download_video(self):
        """Downloads the video.

        If self.client.cache_enabled is True, then the disk cache is used.

        Returns:
            The path where the video has been saved.

        Raises:
            DownloadError: If the video cannot be downloaded.
        """
        rvideo_path = self.presentation.metadata['video_path']

        if self.presentation.client.cache:
            video_path = self.presentation.client.cache.get_path(rvideo_path)
            if not video_path:
                video_path = self.download_video_no_cache()
                self.presentation.client.cache.put_path(rvideo_path, video_path)
        else:
            video_path = self.download_video_no_cache()

        return video_path