Return the OGC WKT which corresponds to the CRS as HTML.

        For example::

            >>> print(get(27700).as_html())  # doctest: +ELLIPSIS
            <div class="syntax"><pre><span class="gh">PROJCS</span><span...

def as_html(self):
        """
        Return the OGC WKT which corresponds to the CRS as HTML.

        For example::

            >>> print(get(27700).as_html())  # doctest: +ELLIPSIS
            <div class="syntax"><pre><span class="gh">PROJCS</span><span...

        """
        url = '{prefix}{code}.html?download'.format(prefix=EPSG_IO_URL,
                                                    code=self.id)
        return requests.get(url).text