Apply suggestion to calorimeters/simple_checking.cxx

calorimeters/simple_checking.cxx

@@ -108,7 +108,7 @@ std::cout << "testing 3\n";
 std::cout << "testing 4\n";
   auto h0 = d1.Histo1D(TH1D("h0", "nhits; ", 20, 0,20), "nhits");
 
-  auto n0 = d1.Count();
+  auto n0 = d1.Filter([](int n){ return (n>=0); },{"nhits"}).Count();
 
   TCanvas* c = new TCanvas();