How to use the svgis.style.add_style function in svgis

def testAddStyleNoDefs(self):
        svg = self.svg.replace('', '')
        new = style.add_style(svg, self.css)
        result = minidom.parseString(new).getElementsByTagName('defs').item(0).getElementsByTagName('style').item(0)
        assert self.css in result.toxml()

def test_add_style(self):
        new = style.add_style(self.file, self.css)
        result = minidom.parseString(new).getElementsByTagName('defs').item(0).getElementsByTagName('style').item(0)
        assert self.css in result.toxml()

def test_replace_style(self):
        new = style.add_style(self.file, self.css, replace=True)
        result = minidom.parseString(new).getElementsByTagName('defs').item(0).getElementsByTagName('style').item(0)
        assert self.css in result.toxml()

def test_add_style_missing_def(self):
        with open(self.file) as f:
            replaced_svg = re.sub(r'', '', f.read())

        try:
            io_svg = BytesIO(replaced_svg)
        except TypeError:
            io_svg = StringIO(replaced_svg)

        new = style.add_style(io_svg, self.css)
        result = minidom.parseString(new).getElementsByTagName('defs').item(0).getElementsByTagName('style').item(0)
        self.assertIn(self.css, result.toxml())

def testAddCli(self):
        result = style.add_style(self.file, self.css)
        self.assertIn(self.css, result[0:2000])

        cssfile = 'tmp.css'

        with open(cssfile, 'w') as w:
            w.write(self.css)

        try:
            result = style.add_style(self.file, cssfile)
            self.assertIn(self.css, result[0:2000])

        finally:
            os.remove('tmp.css')

def testAddCli(self):
        result = style.add_style(self.file, self.css)
        self.assertIn(self.css, result[0:2000])

        cssfile = 'tmp.css'

        with open(cssfile, 'w') as w:
            w.write(self.css)

        try:
            result = style.add_style(self.file, cssfile)
            self.assertIn(self.css, result[0:2000])

        finally:
            os.remove('tmp.css')

def style(layer, output, **kwargs):
    """Add or inline the CSS styles of an SVG"""
    result = _style.add_style(layer, kwargs['style'], kwargs['replace'])
    if kwargs['inline']:
        result = _style.inline(result)
    click.echo(result.encode('utf-8'), file=output)