typedef ROOT::Math::DisplacementVector2D<ROOT::Math::Cartesian2D<Double32_t>,ROOT::Math::DefaultCoordinateSystemTag>::CoordinateSystemTag

ROOT::Math::DisplacementVector2D<ROOT::Math::Cartesian2D<Double32_t>,ROOT::Math::DefaultCoordinateSystemTag>::CoordinateSystemTag is a typedef to ROOT::Math::DefaultCoordinateSystemTag