code: def add_abs_path_directories(opts_dict):
      
      assert_has_input_output(opts_dict)
      opts_dict['abs_input'] = path.abspath(opts_dict['input'])
      if opts_dict['is_dir']:
          # Only add path separator to input if it is a directory
          opts_dict['abs_input'] += get_path_separator()
      opts_dict['abs_output'] = path.abspath(opts_dict['output']) + \
          get_path_separator()
docs: Adds 'abs_input' and 'abs_output' to opts_dict
  
      :param opts_dict: dictionary that will be modified