code: public void setFallbackImageAsset(com.google.api.ads.admanager.axis.v201808.CreativeAsset fallbackImageAsset) {
          this.fallbackImageAsset = fallbackImageAsset;
      }
docs: Sets the fallbackImageAsset value for this BaseFlashCreative.
  
  @param fallbackImageAsset   * The image asset to fall back on if the flash creative cannot
  be loaded. To view
  the fallback image, use the {@link CreativeAsset#assetUrl}.