def path(self, which=None):
        """Extend ``nailgun.entity_mixins.Entity.path``.
        The format of the returned path depends on the value of ``which``:

        download_html
            /api/compliance/arf_reports/:id/download_html

        Otherwise, call ``super``.

        """
        if which in ('download_html',):
            return '{0}/{1}'.format(
                super(ArfReport, self).path(which='self'),
                which
            )
        return super(ArfReport, self).path(which)