let rec filter_outputs_one_level_acc (oes: output_event list) (run_lev: level) (levs: level list) (acc: output_event list): output_event list =
match oes with
| [] -> acc
| oe::oes2 ->
filter_outputs_one_level_acc oes2 run_lev levs
(List.append acc (filter_one_output oe run_lev levs))