code: @Override
      public DescribeTargetGroupsResult describeTargetGroups(DescribeTargetGroupsRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeTargetGroups(request);
      }
docs: <p>
  Describes the specified target groups or all of your target groups. By default, all target groups are described.
  Alternatively, you can specify one of the following to filter the results: the ARN of the load balancer, the
  names of one or more target groups, or the ARNs of one or more target groups.
  </p>
  <p>
  To describe the targets for a target group, use <a>DescribeTargetHealth</a>. To describe the attributes of a
  target group, use <a>DescribeTargetGroupAttributes</a>.
  </p>
  
  @param describeTargetGroupsRequest
  @return Result of the DescribeTargetGroups operation returned by the service.
  @throws LoadBalancerNotFoundException
  The specified load balancer does not exist.
  @throws TargetGroupNotFoundException
  The specified target group does not exist.
  @sample AmazonElasticLoadBalancing.DescribeTargetGroups
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/elasticloadbalancingv2-2015-12-01/DescribeTargetGroups"
  target="_top">AWS API Documentation</a>