Tuning the GENIE pion production model with MINERvA data by Stowell, P, Pickering, L, Willkinson, C, Wret, C, Akbar, F, Andrade, DA, Ascencio, MV, Bellantoni, L, Bercellie, A, Betancourt, M, Bodek, A, Bravar, A, Budd, H, Caceres, G, Cai, T, Cameiro, MF, Chaves, J, Da Motta, H, Dytman, SA, Diaz, GA, Felix, J, Fields, L, Filkins, A, Fine, R, Fiza, N