code: function () {
              if (!this.active) {
                  /**
                   * ### on(GPTEventName, callback)
                   * Can be one of:
                   * * slotRenderEnded
                   * * impressionViewable
                   * * slotOnload
                   * * slotVisibilityChanged
                   * @see util/bind-gpt-events.js
                   */
                  bindGPTEvents(events, slot);
  
                  // Attach GPT services and flag this slot as active.
                  slot.addService(googletag.pubads());
                  if (this.companion) {
                      slot.addService(googletag.companionAds());
                  }
                  this.active = true;
              }
          }
docs: ### activate()
  *Danger Zone*
  @api private