code: @Override
      public DescribeCacheEngineVersionsResult describeCacheEngineVersions(DescribeCacheEngineVersionsRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeCacheEngineVersions(request);
      }
docs: <p>
  Returns a list of the available cache engines and their versions.
  </p>
  
  @param describeCacheEngineVersionsRequest
  Represents the input of a <code>DescribeCacheEngineVersions</code> operation.
  @return Result of the DescribeCacheEngineVersions operation returned by the service.
  @sample AmazonElastiCache.DescribeCacheEngineVersions
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/elasticache-2015-02-02/DescribeCacheEngineVersions"
  target="_top">AWS API Documentation</a>