Return a location point by address.

        :param str query: The address or query you wish to geocode.

        :param bool exactly_one: Return one result or a list of results, if
            available.

        :param int timeout: Time, in seconds, to wait for the geocoding service
            to respond before raising a :class:`geopy.exc.GeocoderTimedOut`
            exception. Set this only if you wish to override, on this call
            only, the value set during the geocoder's initialization.

        :param location_bias: The coordinates to used as location bias.

        :param str language: Preferred language in which to return results.

        :param int limit: Limit the number of returned results, defaults to no
            limit.

            .. versionadded:: 1.12.0

        :param osm_tag: The expression to filter (include/exclude) by key and/
            or value, str as ``'key:value'`` or list/set of str if multiple
            filters are required as ``['key:!val', '!key', ':!value']``.
        :type osm_tag: str or list or set

        :rtype: ``None``, :class:`geopy.location.Location` or a list of them, if
            ``exactly_one=False``.

def geocode(
            self,
            query,
            exactly_one=True,
            timeout=DEFAULT_SENTINEL,
            location_bias=None,
            language=False,
            limit=None,
            osm_tag=None
    ):
        """
        Return a location point by address.

        :param str query: The address or query you wish to geocode.

        :param bool exactly_one: Return one result or a list of results, if
            available.

        :param int timeout: Time, in seconds, to wait for the geocoding service
            to respond before raising a :class:`geopy.exc.GeocoderTimedOut`
            exception. Set this only if you wish to override, on this call
            only, the value set during the geocoder's initialization.

        :param location_bias: The coordinates to used as location bias.

        :param str language: Preferred language in which to return results.

        :param int limit: Limit the number of returned results, defaults to no
            limit.

            .. versionadded:: 1.12.0

        :param osm_tag: The expression to filter (include/exclude) by key and/
            or value, str as ``'key:value'`` or list/set of str if multiple
            filters are required as ``['key:!val', '!key', ':!value']``.
        :type osm_tag: str or list or set

        :rtype: ``None``, :class:`geopy.location.Location` or a list of them, if
            ``exactly_one=False``.

        """
        params = {
            'q': self.format_string % query
        }
        if limit:
            params['limit'] = int(limit)
        if exactly_one:
            params['limit'] = 1
        if language:
            params['lang'] = language
        if location_bias:
            try:
                lat, lon = self._coerce_point_to_string(location_bias).split(',')
                params['lon'] = lon
                params['lat'] = lat
            except ValueError:
                raise ValueError(("Location bias must be a"
                                  " coordinate pair or Point"))
        if osm_tag:
            if isinstance(osm_tag, string_compare):
                params['osm_tag'] = [osm_tag]
            else:
                if not isinstance(osm_tag, (list, set)):
                    raise ValueError(
                        "osm_tag must be a string expression or "
                        "a set/list of string expressions"
                    )
                params['osm_tag'] = osm_tag
        url = "?".join((self.api, urlencode(params, doseq=True)))
        logger.debug("%s.geocode: %s", self.__class__.__name__, url)
        return self._parse_json(
            self._call_geocoder(url, timeout=timeout),
            exactly_one
        )