public com.google.cloud.vision.v1p3beta1.Product.KeyValue getProductLabels(int index) {
      if (productLabelsBuilder_ == null) {
        return productLabels_.get(index);
      } else {
        return productLabelsBuilder_.getMessage(index);
      }
    }
<pre>
Key-value pairs that can be attached to a product. At query time,
constraints can be specified based on the product_labels.

Note that integer values can be provided as strings, e.g. "1199". Only
strings with integer values can match a range-based restriction which is
to be supported soon.

Multiple values can be assigned to the same key. One product may have up to
100 product_labels.
</pre>

<code>repeated .google.cloud.vision.v1p3beta1.Product.KeyValue product_labels = 5;</code>
java-vision/proto-google-cloud-vision-v1p3beta1/src/main/java/com/google/cloud/vision/v1p3beta1/Product.java