code: public com.google.api.ads.adwords.axis.v201809.cm.AdUnionId getAdUnionId() {
          return adUnionId;
      }
docs: Gets the adUnionId value for this TemplateAd.
  
  @return adUnionId   * Group ID of all template ads, which should be created together.
  Template ads in the same union reference the same data but have different
  dimensions. Single ads do not have a union ID. If a template ad specifies
  an ad union with only one ad, no union will be created.
  <span class="constraint Selectable">This field
  can be selected using the value "TemplateAdUnionId".</span>