code: public void setYouTubeVideos(com.google.api.ads.adwords.axis.v201809.cm.AssetLink[] youTubeVideos) {
          this.youTubeVideos = youTubeVideos;
      }
docs: Sets the youTubeVideos value for this MultiAssetResponsiveDisplayAd.
  
  @param youTubeVideos   * The YouTube videos of the ad. Optional. Support up to 5 youtube
  videos. Asset.assetId must be
  populated in this field.
  <span class="constraint Selectable">This field
  can be selected using the value "MultiAssetResponsiveDisplayAdYouTubeVideos".</span>