set svg(svg) {
    this.__svg = svg;
    if (svg === undefined || svg === null) {
      this._renderSvg(nothing);
    } else {
      this._renderSvg(unwrapSvg(svg));
    }
  }
On IE11, svgs without focusable false appear in the tab order
so make sure to have <svg focusable="false"> in svg files
@param {TemplateResult|nothing|TagFunction} svg