Comment on “Szekeres universes with homogeneous scalar fields” Ismael Delgado Gaspar, Roberto A. Sussman, David D. McNutt and Alan A. Coley Eur. Phys. J. C, 81 4 (2021) 310 Published online: 12 April 2021 DOI: 10.1140/epjc/s10052-021-09113-9