docs: public static void removeCSSClass(Element e, String cssclass) {
      String oldval = e.getAttribute(SVGConstants.SVG_CLASS_ATTRIBUTE);
      if(oldval == null) {
        return;
      }
      String[] classes = oldval.split(" ");
      if(classes.length == 1) {
        if(cssclass.equals(classes[0])) {
          e.removeAttribute(SVGConstants.SVG_CLASS_ATTRIBUTE);
        }
      }
      else if(classes.length == 2) {
        if(cssclass.equals(classes[0])) {
          if(cssclass.equals(classes[1])) {
            e.removeAttribute(SVGConstants.SVG_CLASS_ATTRIBUTE);
          }
          else {
            e.setAttribute(SVGConstants.SVG_CLASS_ATTRIBUTE, classes[1]);
          }
        }
        else if(cssclass.equals(classes[1])) {
          e.setAttribute(SVGConstants.SVG_CLASS_ATTRIBUTE, classes[0]);
        }
      }
      else {
        StringBuilder joined = new StringBuilder();
        for(String c : classes) {
          if(!c.equals(cssclass)) {
            if(joined.length() > 0) {
              joined.append(' ');
            }
            joined.append(c);
          }
        }
        e.setAttribute(SVGConstants.SVG_CLASS_ATTRIBUTE, joined.toString());
      }
    }