code: @Override
      public OptInPhoneNumberResult optInPhoneNumber(OptInPhoneNumberRequest request) {
          request = beforeClientExecution(request);
          return executeOptInPhoneNumber(request);
      }
docs: <p>
  Use this request to opt in a phone number that is opted out, which enables you to resume sending SMS messages to
  the number.
  </p>
  <p>
  You can opt in a phone number only once every 30 days.
  </p>
  
  @param optInPhoneNumberRequest
  Input for the OptInPhoneNumber action.
  @return Result of the OptInPhoneNumber operation returned by the service.
  @throws ThrottledException
  Indicates that the rate at which requests have been submitted for this action exceeds the limit for your
  account.
  @throws InternalErrorException
  Indicates an internal service error.
  @throws AuthorizationErrorException
  Indicates that the user has been denied access to the requested resource.
  @throws InvalidParameterException
  Indicates that a request parameter does not comply with the associated constraints.
  @sample AmazonSNS.OptInPhoneNumber
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/sns-2010-03-31/OptInPhoneNumber" target="_top">AWS API
  Documentation</a>