Procs

proc markdown(notebook: JupyterNotebook): string {...}{.raises: [ValueError],
    tags: [].}

proc export_images(notebook: JupyterNotebook; path: string = "./images";
                   prefix: string = "image") {...}{.
    raises: [OSError, IOError, ValueError],
    tags: [ReadDirEffect, WriteDirEffect, WriteIOEffect].}