code: @Override
      public AddTagsResult addTags(AddTagsRequest request) {
          request = beforeClientExecution(request);
          return executeAddTags(request);
      }
docs: <p>
  Adds the specified tags to the specified Elastic Load Balancing resource. You can tag your Application Load
  Balancers, Network Load Balancers, and your target groups.
  </p>
  <p>
  Each tag consists of a key and an optional value. If a resource already has a tag with the same key,
  <code>AddTags</code> updates its value.
  </p>
  <p>
  To list the current tags for your resources, use <a>DescribeTags</a>. To remove tags from your resources, use
  <a>RemoveTags</a>.
  </p>
  
  @param addTagsRequest
  @return Result of the AddTags operation returned by the service.
  @throws DuplicateTagKeysException
  A tag key was specified more than once.
  @throws TooManyTagsException
  You've reached the limit on the number of tags per load balancer.
  @throws LoadBalancerNotFoundException
  The specified load balancer does not exist.
  @throws TargetGroupNotFoundException
  The specified target group does not exist.
  @sample AmazonElasticLoadBalancing.AddTags
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/elasticloadbalancingv2-2015-12-01/AddTags" target="_top">AWS
  API Documentation</a>