How to use the branca.element.CssLink function in branca

else:
            keys = None
        self.test_params(keys=keys)
        super(Search, self).render()

        figure = self.get_root()
        assert isinstance(figure, Figure), ('You cannot render this Element '
                                            'if it is not in a Figure.')

        figure.header.add_child(
            JavascriptLink('https://cdn.jsdelivr.net/npm/leaflet-search@2.9.7/dist/leaflet-search.min.js'),  # noqa
            name='Leaflet.Search.js'
        )

        figure.header.add_child(
            CssLink('https://cdn.jsdelivr.net/npm/leaflet-search@2.9.7/dist/leaflet-search.min.css'),  # noqa
            name='Leaflet.Search.css'
        )

def render(self, **kwargs):
        super(MarkerCluster, self).render(**kwargs)

        figure = self.get_root()
        assert isinstance(figure, Figure), ('You cannot render this Element '
                                            'if it is not in a Figure.')

        figure.header.add_child(
            JavascriptLink('https://cdnjs.cloudflare.com/ajax/libs/leaflet.markercluster/1.1.0/leaflet.markercluster.js'),  # noqa
            name='markerclusterjs')

        figure.header.add_child(
            CssLink('https://cdnjs.cloudflare.com/ajax/libs/leaflet.markercluster/1.1.0/MarkerCluster.css'),  # noqa
            name='markerclustercss')

        figure.header.add_child(
            CssLink('https://cdnjs.cloudflare.com/ajax/libs/leaflet.markercluster/1.1.0/MarkerCluster.Default.css'),  # noqa
            name='markerclusterdefaultcss')

def render(self, **kwargs):
        figure = self.get_root()
        assert isinstance(figure, Figure), ('You cannot render this Element '
                                            'if it is not in a Figure.')
        super(MiniMap, self).render()

        figure.header.add_child(JavascriptLink('https://cdnjs.cloudflare.com/ajax/libs/leaflet-minimap/3.6.1/Control.MiniMap.js'))  # noqa

        figure.header.add_child(CssLink('https://cdnjs.cloudflare.com/ajax/libs/leaflet-minimap/3.6.1/Control.MiniMap.css'))  # noqa

name='jqueryui1.10.2')

        figure.header.add_child(
            JavascriptLink('https://rawcdn.githack.com/nezasa/iso8601-js-period/master/iso8601.min.js'),  # noqa
            name='iso8601')

        figure.header.add_child(
            JavascriptLink('https://rawcdn.githack.com/socib/Leaflet.TimeDimension/master/dist/leaflet.timedimension.min.js'),  # noqa
            name='leaflet.timedimension')

        figure.header.add_child(
            CssLink('https://cdnjs.cloudflare.com/ajax/libs/highlight.js/8.4/styles/default.min.css'),  # noqa
            name='highlight.js_css')

        figure.header.add_child(
            CssLink('http://apps.socib.es/Leaflet.TimeDimension/dist/leaflet.timedimension.control.min.css'),  # noqa
            name='leaflet.timedimension_css')

def render(self, **kwargs):
        super(Fullscreen, self).render()

        figure = self.get_root()
        assert isinstance(figure, Figure), ('You cannot render this Element '
                                            'if it is not in a Figure.')

        figure.header.add_child(
            JavascriptLink('https://cdnjs.cloudflare.com/ajax/libs/leaflet.fullscreen/1.4.2/Control.FullScreen.min.js'),  # noqa
            name='Control.Fullscreen.js'
        )

        figure.header.add_child(
            CssLink('https://cdnjs.cloudflare.com/ajax/libs/leaflet.fullscreen/1.4.2/Control.FullScreen.min.css'),  # noqa
            name='Control.FullScreen.css'
        )

def render(self, **kwargs):
        super(Crossfilter, self).render(**kwargs)

        figure = self._parent.get_root()
        assert isinstance(figure, Figure), (
            "You cannot render this Element if it's not in a Figure.")

        figure.header.add_child(
            CssLink("https://cdnjs.cloudflare.com/ajax/libs/dc/1.7.5/dc.css"),
            name='dcjs_css')
        figure.header.add_child(
            CssLink("https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.3/leaflet.css"),
            name='leaflet_css')
        figure.header.add_child(
            CssLink("https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css"),
            name='bootstrap_css')

        figure.header.add_child(
            JavascriptLink("https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js"),
            name='d3js')
        figure.header.add_child(
            JavascriptLink("https://cdnjs.cloudflare.com/ajax/libs/crossfilter/1.3.12/crossfilter.min.js"),  # noqa
            name='crossfilterjs')
        figure.header.add_child(
            JavascriptLink("https://cdnjs.cloudflare.com/ajax/libs/dc/2.0.0-beta.20/dc.js"),
            name='dcjs')
        figure.header.add_child(
            JavascriptLink("https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.3/leaflet.js"),
            name='leaflet')
        figure.header.add_child(
            JavascriptLink("https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"),  # noqa

name='jquery2.0.0')

        figure.header.add_child(
            JavascriptLink('https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.10.2/jquery-ui.min.js'),  # noqa
            name='jqueryui1.10.2')

        figure.header.add_child(
            JavascriptLink('https://rawcdn.githack.com/nezasa/iso8601-js-period/master/iso8601.min.js'),  # noqa
            name='iso8601')

        figure.header.add_child(
            JavascriptLink('https://rawcdn.githack.com/socib/Leaflet.TimeDimension/master/dist/leaflet.timedimension.min.js'),  # noqa
            name='leaflet.timedimension')

        figure.header.add_child(
            CssLink('https://cdnjs.cloudflare.com/ajax/libs/highlight.js/8.4/styles/default.min.css'),  # noqa
            name='highlight.js_css')

        figure.header.add_child(
            CssLink("https://rawcdn.githack.com/socib/Leaflet.TimeDimension/master/dist/leaflet.timedimension.control.min.css"),  # noqa
            name='leaflet.timedimension_css')

        figure.header.add_child(
            JavascriptLink('https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.18.1/moment.min.js'),
            name='moment')

def render(self, **kwargs):
        super(Draw, self).render(**kwargs)

        figure = self.get_root()
        assert isinstance(figure, Figure), ('You cannot render this Element '
                                            'if it is not in a Figure.')

        figure.header.add_child(
            JavascriptLink('https://cdnjs.cloudflare.com/ajax/libs/leaflet.draw/1.0.2/leaflet.draw.js'))  # noqa
        figure.header.add_child(
            CssLink('https://cdnjs.cloudflare.com/ajax/libs/leaflet.draw/1.0.2/leaflet.draw.css'))  # noqa

        export_style = """
            <style>
                #export {
                    position: absolute;
                    top: 5px;
                    right: 10px;
                    z-index: 999;
                    background: white;
                    color: black;
                    padding: 6px;
                    border-radius: 4px;
                    font-family: 'Helvetica Neue';
                    cursor: pointer;
                    font-size: 12px;
                    text-decoration: none;</style>

name='jquery2.0.0')

        figure.header.add_child(
            JavascriptLink('https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.10.2/jquery-ui.min.js'),  # noqa
            name='jqueryui1.10.2')

        figure.header.add_child(
            JavascriptLink('https://rawcdn.githack.com/nezasa/iso8601-js-period/master/iso8601.min.js'),  # noqa
            name='iso8601')

        figure.header.add_child(
            JavascriptLink('https://rawcdn.githack.com/socib/Leaflet.TimeDimension/master/dist/leaflet.timedimension.min.js'),  # noqa
            name='leaflet.timedimension')

        figure.header.add_child(
            CssLink('https://cdnjs.cloudflare.com/ajax/libs/highlight.js/8.4/styles/default.min.css'),  # noqa
            name='highlight.js_css')

        figure.header.add_child(
            CssLink('http://apps.socib.es/Leaflet.TimeDimension/dist/leaflet.timedimension.control.min.css'),  # noqa
            name='leaflet.timedimension_css')

def render(self, **kwargs):
        super(Crossfilter, self).render(**kwargs)

        figure = self._parent.get_root()
        assert isinstance(figure, Figure), (
            "You cannot render this Element if it's not in a Figure.")

        figure.header.add_child(
            CssLink("https://cdnjs.cloudflare.com/ajax/libs/dc/1.7.5/dc.css"),
            name='dcjs_css')
        figure.header.add_child(
            CssLink("https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.3/leaflet.css"),
            name='leaflet_css')
        figure.header.add_child(
            CssLink("https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css"),
            name='bootstrap_css')

        figure.header.add_child(
            JavascriptLink("https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js"),
            name='d3js')
        figure.header.add_child(
            JavascriptLink("https://cdnjs.cloudflare.com/ajax/libs/crossfilter/1.3.12/crossfilter.min.js"),  # noqa
            name='crossfilterjs')
        figure.header.add_child(
            JavascriptLink("https://cdnjs.cloudflare.com/ajax/libs/dc/2.0.0-beta.20/dc.js"),