+/*
+ Class used for extracting the signal from an invariant mass spectrum.
+ It implements the AliDielectronSignalBase class and uses the like-sign
+ substraction method for estimating the signal and background.
+ There is no fitting in this class, only bin counting.
+
+ Example usage:
+ AliDielectronSignalExt *signalProcess = new AliDielectronSignalExt();
+ TObjArray *histoArray = new TObjArray();
+ histoArray->Add(signalPP); // the order of putting the histograms in the array is important!!
+ histoArray->Add(signalPM);
+ histoArray->Add(signalMM);
+ signalProcess->SetMethod(AliDielectronSignalBase::kLikeSign); // or kEventMixing
+ signalProcess->SetIntegralRange(3.0,3.15); // J/Psi peak
+ signalProcess->SetRebin(2); // rebin the histograms
+ signalProcess->Process(histoArray);
+ signalProcess->Draw("stat");
+ signalProcess->Print();
+
+*/
+