const auto nEntries = 3;
ROOT::RDataFrame _df(nEntries);
auto df = _df.Define("one", [] { return 1; }).Define("two", [] { return 2; });

auto isOne = [] (int a) { return a == 1; };
auto isNotOne = ROOT::RDF::Not(isOne);

auto c1 = df.Filter(isOne, {"one"}).Count();
auto c2 = df.Filter(isNotOne, {"two"}).Count();

R__ASSERT(*c1 == nEntries);
R__ASSERT(*c2 == nEntries);

auto checkOneTwo = [] (const std::vector<int> &v) { return v.size() == 2 && v[0] == 1 && v[1] == 2; };

auto c3 = df.Filter(ROOT::RDF::PassAsVec<2, int>(checkOneTwo), {"one", "two"}).Count();
R__ASSERT(*c3 == nEntries);

gROOT->GetListOfCanvases()->Draw()