Trying to append to Style (css)

[Neon22]

I have successfully made an initial style and added it under defs. but cannot append a new css style to this.

def create_CSS_styles(self):
        bg = (100,220,200)
        css = ".background { fill:"+svgwrite.rgb(*bg)+"; }\n"
        c = ["whitesquare", (200,200,0), (50,200,200)]
        css += "."+c[0]+" {fill:"+svgwrite.rgb(*c[1])+"; stroke:"+svgwrite.rgb(*c[2])+"}\n"
        self.dwg.defs.add(self.dwg.style(css))

This style is accessible and works as expected. Thanks.

The docs say I can append to this style element but I cant get it to work.

• https://svgwrite.readthedocs.io/en/latest/classes/style.html

I can't find any code exercising this append() yet.
I've tried numerous variations. Including this:

def add_style(self, name, attributes):
        "use self.dwg.style.append() "
        c = ["blacksquare", (200,90,90), (50,200,200)]
        css = "."+c[0]+" {fill:"+svgwrite.rgb(*c[1])+"; stroke:"+svgwrite.rgb(*c[2])+"}\n"
        s = self.dwg.defs.get_xml().find("style")
        print(s)
        print(dir(s))
        #s.append(css)
        s.append(self.dwg.style(css))#.get_xml())

Any help on the right way to add a new css style to the existing style section under defs is greatly appreciated.