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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_sites(self, entry):
 """ Return the sites linked in HTML. """

        try:
            index_url = reverse('zinnia:entry_archive_index')
        except NoReverseMatch:
            index_url = ''
        return format_html_join(
            ', ', '<a href="{}://{}{}" target="blank">{}</a>',
            [(settings.PROTOCOL, site.domain, index_url,
              conditional_escape(site.name)) for site in entry.sites.all()])