def add_sidenotes(html: str,
                  toggle_class: str = "sidenote-toggle",
                  label_class: str  = "sidenote-number") -> str:
    counter: int = 0
    start: int = html.find("[°")
    while start > -1:
        counter += 1
        end: int = html.find("]", start)
        text: str = html[start + 2:end]
        sidenote: str = f"<label for=\"sn-{counter}\" class=\"{toggle_class} {label_class}\"></label>\n" +\
                        f"<input type=\"checkbox\" id=\"sn-{counter}\" class=\"{toggle_class}\" />\n" +\
                        f"<span class=\"sidenote\">\n" +\
                        f"    {text}\n" +\
                        f"</span>\n"
        html = html[:start] + sidenote + html[end + 1:]
        start = html.find("[°", start + len(sidenote))
    return html