code: public void setSmartSizeMode(com.google.api.ads.admanager.axis.v201811.SmartSizeMode smartSizeMode) {
          this.smartSizeMode = smartSizeMode;
      }
docs: Sets the smartSizeMode value for this AdUnit.
  
  @param smartSizeMode   * The smart size mode for this ad unit. This attribute is optional
  and defaults to {@link
  SmartSizeMode#NONE} for fixed sizes.