code: function adSize(slot) {
    if (slot.params.cf) {
      const size = slot.params.cf.toUpperCase().split('X');
      const width = parseInt(slot.params.cw || size[0], 10);
      const height = parseInt(slot.params.ch || size[1], 10);
      return [width, height];
    }
    return [1, 1];
  }
docs: Determines the AdSize for the slot.