When decoding an "OXM" field, now it is possible to accept and empty tuple or list. The value and the mask are considered as "None". Closes-Bug: #2133487 Signed-off-by: lajoskatona <lajos.katona@est.tech> Co-Authored-By: Rodolfo Alonso Hernandez <ralonsoh@redhat.com> Change-Id: I9069337270cc261974c524a5ab284b055177ab3e