xxx1okxxx2 | ["yya", "yyb", "ok"] | Pair(a: "zza", b: "ok")
ww1ok2 | okok! | uuuu?ok
{"kk": "kk1", "kkx": "ok"}
failed at 1 | ["-"] | Pair(a: "-", b: "-")
failed at 1 | failed at 1 | failed at 1
{"-": "-"}
index: failed
0 qqaokqqb
2 qqaokqqb
before break: 0 qqaokqqb
{"a": 1, "c": 3}
{"a": 10, "c": 30}