docs: def add_to_pairtree(output_path, meta_id):
      """Creates pairtree dir structure within pairtree for new
      element."""
      # create the pair path
      paired_path = pair_tree_creator(meta_id)
      path_append = ''
      # for each directory in the pair path
      for pair_dir in paired_path.split(os.sep):
          # append the pair path together, one directory at a time
          path_append = os.path.join(path_append, pair_dir)
          # append the pair path to the output path
          combined_path = os.path.join(output_path, path_append)
          # if the path doesn't already exist, create it
          if not os.path.exists(combined_path):
              os.mkdir(combined_path)
      return combined_path