code: private void stage6(ProtoNetwork pn) {
          beginStage(PHASE3_STAGE6_HDR, "6", NUM_PHASES);
          stageOutput("Saving augmented network");
  
          final String rootpath = artifactPath.getAbsolutePath();
          long t1 = currentTimeMillis();
          try {
              p3.write(rootpath, pn);
  
              if (withDebug()) {
                  try {
                      TextProtoNetworkExternalizer textExternalizer =
                              new TextProtoNetworkExternalizer();
                      textExternalizer.writeProtoNetwork(pn,
                              rootpath);
                  } catch (ProtoNetworkError e) {
                      error("Could not write out equivalenced proto network.");
                  }
              }
          } catch (ProtoNetworkError e) {
              stageError(e.getUserFacingMessage());
              bail(NO_PROTO_NETWORKS_SAVED);
          }
          long t2 = currentTimeMillis();
  
          final StringBuilder bldr = new StringBuilder();
          markTime(bldr, t1, t2);
          markEndStage(bldr);
          stageOutput(bldr.toString());
      }
docs: Runs stage six network saving.
  
  @param pn Proto-network