void test_RooKeys(bool useRooKeys=true, double rho = 10){
  using namespace RooFit;

  Int_t to_gen = 1e5; //1e6;

  RooRealVar m("m","m",5000,5500);
  RooRealVar mean("mean", "mean", 5279);
  RooRealVar cc("cc", "cc", 0.1);
  RooRealVar pp("pp", "pp", 1.);
  RooArgusBG* gen_pdf = new RooArgusBG("argus", "argus", m, mean, cc, pp);
  RooDataSet* ds = (RooDataSet*) gen_pdf->generate(RooArgSet(m), to_gen);


    // use TKDE
  std::vector<double> xdata(to_gen);

  auto h1 = new TH1D("h1","h1",200,5000,5500);
  for (size_t i = 0; i < xdata.size(); i++) {
     xdata[i] = ds->get(i)->getRealValue("m");
     h1->Fill(xdata[i]);
  }
  auto tkde = new TKDE(to_gen, xdata.data(), m.getMin(), m.getMax(),"KernelType:Gaussian;Iteration:Adaptive;Mirror:MirrorLeft;Binning:RelaxedBinning", rho);


  std::cout << "create tkde" << std::endl;
  auto f1 = tkde->GetFunction(100);
  h1->Scale(1/h1->Integral(),"width");
  h1->Draw();
  f1->Draw("same");
  gPad->Update();
  
  
  ROOT::Math::Functor1D functor([&](double x) { return (*tkde)(x);});
  auto kpdf = new RooFunctor1DPdfBinding ("rookeys2", "rookeys2", functor, m);

  RooAbsPdf * rookeys = nullptr;
  if (useRooKeys) { 
     cout << "now fitting with RooKeys" << endl;
     rookeys = new RooKeysPdf("rookeys", "rookeys", m, *ds, RooKeysPdf::MirrorBoth, 0.8);
  }

  
  cout << "validation plot" << endl;

  RooPlot* myframe=m.frame(Bins(50),Name("M"),Title("M"));
  ds->plotOn(myframe,MarkerSize(0.9));
  kpdf->plotOn(myframe, LineColor(kRed));
  if (rookeys) rookeys->plotOn(myframe, LineColor(kBlue));

  TCanvas* mycanvas = new TCanvas ("mycanvas","Fit", 800, 550);
  myframe->Draw();
}