code: def tag(placeholders):
      
      # We first recover the name of the file to be tagged...
      template = placeholders.feed.retrieve_config("file_to_tag", "{filename}")
      filename = substitute_placeholders(template, placeholders)
      podpath = os.path.join(placeholders.directory, filename)
      # ... and this is it
  
      # now we create a dictionary of tags and values
      tagdict = placeholders.feed.defaulttagdict  # these are the defaults
      try:  # We do as if there was a section with potential tag info
          feedoptions = placeholders.feed.config.options(placeholders.name)
          # this monstruous concatenation of classes... surely a bad idea.
          tags = [[option.replace("tag_", ""), placeholders.feed.config[
              placeholders.name][option]] for option in feedoptions if "tag_" in
                  option]  # these are the tags to be filled
          if tags:
              for tag in tags:
                  tagdict[tag[0]] = tag[1]
      except configparser.NoSectionError:
          pass
      for tag in tagdict:
          metadata = substitute_placeholders(
              tagdict[tag], placeholders)
          if metadata:
              stagger.util.set_frames(podpath, {tag: metadata})
          else:
              stagger.util.remove_frames(podpath, tag)
docs: Tag the file at podpath with the information in podcast and entry