code: @Override
      public DescribeUserStackAssociationsResult describeUserStackAssociations(DescribeUserStackAssociationsRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeUserStackAssociations(request);
      }
docs: <p>
  Retrieves a list that describes the UserStackAssociation objects. You must specify either or both of the
  following:
  </p>
  <ul>
  <li>
  <p>
  The stack name
  </p>
  </li>
  <li>
  <p>
  The user name (email address of the user associated with the stack) and the authentication type for the user
  </p>
  </li>
  </ul>
  
  @param describeUserStackAssociationsRequest
  @return Result of the DescribeUserStackAssociations operation returned by the service.
  @throws InvalidParameterCombinationException
  Indicates an incorrect combination of parameters, or a missing parameter.
  @sample AmazonAppStream.DescribeUserStackAssociations
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/appstream-2016-12-01/DescribeUserStackAssociations"
  target="_top">AWS API Documentation</a>