code: @Override
      public DescribeDataSourcesResult describeDataSources(DescribeDataSourcesRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeDataSources(request);
      }
docs: <p>
  Returns a list of <code>DataSource</code> that match the search criteria in the request.
  </p>
  
  @param describeDataSourcesRequest
  @return Result of the DescribeDataSources operation returned by the service.
  @throws InvalidInputException
  An error on the client occurred. Typically, the cause is an invalid input value.
  @throws InternalServerException
  An error on the server occurred when trying to process a request.
  @sample AmazonMachineLearning.DescribeDataSources