code: @Override
      public DescribeFleetsResult describeFleets(DescribeFleetsRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeFleets(request);
      }
docs: <p>
  Retrieves a list that describes one or more specified fleets, if the fleet names are provided. Otherwise, all
  fleets in the account are described.
  </p>
  
  @param describeFleetsRequest
  @return Result of the DescribeFleets operation returned by the service.
  @throws ResourceNotFoundException
  The specified resource was not found.
  @sample AmazonAppStream.DescribeFleets
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/appstream-2016-12-01/DescribeFleets" target="_top">AWS API
  Documentation</a>