code: @Override
      public CreateSubscriptionResult createSubscription(CreateSubscriptionRequest request) {
          request = beforeClientExecution(request);
          return executeCreateSubscription(request);
      }
docs: <p>
  Activates AWS Shield Advanced for an account.
  </p>
  <p>
  As part of this request you can specify <code>EmergencySettings</code> that automaticaly grant the DDoS response
  team (DRT) needed permissions to assist you during a suspected DDoS attack. For more information see <a
  href="https://docs.aws.amazon.com/waf/latest/developerguide/authorize-DRT.html">Authorize the DDoS Response Team
  to Create Rules and Web ACLs on Your Behalf</a>.
  </p>
  <p>
  When you initally create a subscription, your subscription is set to be automatically renewed at the end of the
  existing subscription period. You can change this by submitting an <code>UpdateSubscription</code> request.
  </p>
  
  @param createSubscriptionRequest
  @return Result of the CreateSubscription operation returned by the service.
  @throws InternalErrorException
  Exception that indicates that a problem occurred with the service infrastructure. You can retry the
  request.
  @throws ResourceAlreadyExistsException
  Exception indicating the specified resource already exists.
  @sample AWSShield.CreateSubscription
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/shield-2016-06-02/CreateSubscription" target="_top">AWS API
  Documentation</a>