def _add_footnotes(self, text):
        if self.footnotes:
            footer = [
                '<div class="footnotes">',
                '<hr' + self.empty_element_suffix,
                '<ol>',
            ]
            for i, id in enumerate(self.footnote_ids):
                if i != 0:
                    footer.append('')
                footer.append(id % '<li id="fn-%s">')
                footer.append(self._run_block_gamut(self.footnotes[id]))
                backlink = ('<a href="#fnref-%s" '
                    'class="footnoteBackLink" '
                    'title="Jump back to footnote %d in the text.">'
                    '&#8617;</a>' % (id, i+1))
                if footer[-1].endswith("</p>"):
                    footer[-1] = footer[-1][:-len("</p>")] \
                        + '&#160;' + backlink + "</p>"
                else:
                    footer.append("\n<p>%s</p>" % backlink)
                footer.append('</li>')
            footer.append('</ol>')
            footer.append('</div>')
            return text + '\n\n' + '\n'.join(footer)
        else:
            return text

    # Ampersand-encoding based entirely on Nat Irons's Amputator MT plugin:
    #   http://bumppo.net/projects/amputator/
dataset/ETHPy150Open an0/Letterpress/code/markdown2/lib/markdown2.py/Markdown._add_footnotes/swapped operands of `%`