function CFFSubset(font) {
    var _this13;

    _this13 = _Subset2.call(this, font) || this;
    _this13.cff = _this13.font['CFF '];

    if (!_this13.cff) {
      throw new Error('Not a CFF Font');
    }

    return _this13;
  }
Returns a new font with the given variation settings applied.
Settings can either be an instance name, or an object containing
variation tags as specified by the `variationAxes` property.

@param {object} settings
@return {TTFFont}