code: def toc(self):
          
          output = []
          for key in sorted(self.catalog.keys()):
              edition = self.catalog[key]['edition']
              length = len(self.catalog[key]['transliteration'])
              output.append(
                  "Pnum: {key}, Edition: {edition}, length: {length} line(s)".format(
                      key=key, edition=edition, length=length))
          return output
docs: Returns a rich list of texts in the catalog.