code: @Override
      public CreateUserPoolClientResult createUserPoolClient(CreateUserPoolClientRequest request) {
          request = beforeClientExecution(request);
          return executeCreateUserPoolClient(request);
      }
docs: <p>
  Creates the user pool client.
  </p>
  
  @param createUserPoolClientRequest
  Represents the request to create a user pool client.
  @return Result of the CreateUserPoolClient operation returned by the service.
  @throws InvalidParameterException
  This exception is thrown when the Amazon Cognito service encounters an invalid parameter.
  @throws ResourceNotFoundException
  This exception is thrown when the Amazon Cognito service cannot find the requested resource.
  @throws TooManyRequestsException
  This exception is thrown when the user has made too many requests for a given operation.
  @throws LimitExceededException
  This exception is thrown when a user exceeds the limit for a requested AWS resource.
  @throws NotAuthorizedException
  This exception is thrown when a user is not authorized.
  @throws ScopeDoesNotExistException
  This exception is thrown when the specified scope does not exist.
  @throws InvalidOAuthFlowException
  This exception is thrown when the specified OAuth flow is invalid.
  @throws InternalErrorException
  This exception is thrown when Amazon Cognito encounters an internal error.
  @sample AWSCognitoIdentityProvider.CreateUserPoolClient
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/cognito-idp-2016-04-18/CreateUserPoolClient"
  target="_top">AWS API Documentation</a>