code: def substitute_placeholders(inputstring, placeholders):
      
      newst = inputstring.format(link=placeholders.link,
                                 filename=placeholders.filename,
                                 directory=placeholders.directory,
                                 fullpath=placeholders.fullpath,
                                 title=placeholders.title,
                                 filename_title=placeholders.filename_title,
                                 date=placeholders.date_string(),
                                 podcasttitle=placeholders.podcasttitle,
                                 filename_podcasttitle=
                                 placeholders.filename_podcasttitle,
                                 name=placeholders.name,
                                 subtitle=placeholders.sanitizedsubtitle,
                                 entrysummary=placeholders.entrysummary)
      return newst
docs: Take a string with placeholders, and return the strings with substitutions.