'Return a Zone instance.
(Note that PowerDNS does not support per-zone TTL defaults, so all Zone
objects will have ``ttl=None``.)
:param zone_id: name of the required zone with the trailing period, for
example "example.com.".
:type  zone_id: ``str``
:rtype: :class:`Zone`
:raises: ZoneDoesNotExistError: If no zone could be found.'

def get_zone(self, zone_id):

    action = ('%s/servers/%s/zones/%s' % (self.api_root, self.ex_server, zone_id))
    try:
        response = self.connection.request(action=action, method='GET')
    except BaseHTTPError:
        e = sys.exc_info()[1]
        if (e.code == httplib.UNPROCESSABLE_ENTITY):
            raise ZoneDoesNotExistError(zone_id=zone_id, driver=self, value=e.message)
        raise e
    return self._to_zone(response.object)
