1-prefix_push p1_ 2-options_file_yaml ex47-opt.yml 3-prefix_pop 4 5-prefix_push p1_ 6-options_file_yaml ex47-opt.yml 7-prefix_pop 8 9-prefix_push p2_ 10-options_file_yaml ex47-opt.yml 11-prefix_pop 12 13-prefix_push p3_ 14-options_string_yaml "name: value" 15-prefix_pop 16 17-prefix_push p3_ 18-options_string_yaml "name: value" 19-prefix_pop 20 21-prefix_push p4_ 22-options_string_yaml "name: value" 23-prefix_pop 24