code: public void setSwiffyAsset(com.google.api.ads.admanager.axis.v201902.SwiffyFallbackAsset swiffyAsset) {
          this.swiffyAsset = swiffyAsset;
      }
docs: Sets the swiffyAsset value for this FlashCreative.
  
  @param swiffyAsset   * A Swiffy asset that can be used as a fallback for this flash
  creative.
  This attribute is readonly.