void problem(double range = 1){
  TH1::SetDefaultSumw2();
  TH1D * h_first = new TH1D("h_first", "h_first", 10, -1,1);
  TH1D * h_second = new TH1D("h_first", "h_first", 10, -1,1);
  h_first->FillRandom("pol0");
  h_second->FillRandom("pol0");
  TH1D *h_third = (TH1D*)h_first->Clone("h_third");
  h_third->Divide(h_second); 
  

  RooRealVar x("x","x",-1,1);
  RooDataHist data("data","histo", x, h_third);

  RooRealVar m("m", "m", 0, -range, range);
  RooGenericPdf f_p("f_p", "1 + m*x",RooArgSet(m, x));
  
  f_p.fitTo(data, RooFit::SumW2Error(kTRUE));
  RooPlot *xframe = x.frame();
  data.plotOn(xframe,  RooFit::Name("data")) ;
  f_p.plotOn(xframe, RooFit::Name("f_p"));
  f_p.paramOn(xframe, RooFit::Parameters(RooArgSet(m)), RooFit::Layout(0.32, 0.59,0.35));
  xframe->Draw();

}