code: func (h *Client) ProductImpressionVariant(productImpressionVariant string) *Client {
  	h.productImpressionVariant = productImpressionVariant
  	h.productImpressionVariantSet = true
  	return h
  }
docs: // The variant of the product. Impression List index must be
  // a positive integer between 1 and 200, inclusive. Product
  // index must be a positive integer between 1 and 200, inclusive.
  // For analytics.js the Enhanced Ecommerce plugin must be installed
  // before using this field.