code: def write_exb(docgraph, output_file):
      
      exmaralda_file = ExmaraldaFile(docgraph)
      assert isinstance(output_file, (str, file))
      if isinstance(output_file, str):
          path_to_file = os.path.dirname(output_file)
          if not os.path.isdir(path_to_file):
              create_dir(path_to_file)
          exmaralda_file.write(output_file)
      else:  # output_file is a file object
          output_file.write(exmaralda_file.__str__())
docs: converts a DiscourseDocumentGraph into an Exmaralda ``*.exb`` file and
      writes it to the given file (or file path).