code: public static IPreProcessor unwrap(final IPreProcessor preProcessor) {
          if (preProcessor == null) {
              return null;
          }
          if (preProcessor instanceof PreProcessorWrapper) {
              return ((PreProcessorWrapper) preProcessor).unwrap();
          }
          return preProcessor;
      }
docs: <p>
  Unwraps a wrapped implementation of {@link IPreProcessor}.
  </p>
  <p>
  This method is meant for <strong>internal</strong> use only.
  </p>
  
  @param preProcessor the pre-processor to be unwrapped.
  @return the unwrapped pre-processor.