```erlang 1.rfc4627:encode( {obj,[{"question",<<"bbb">>},{"label",[["1","2"],["2","3"]]}]} ).   "{\"question\":\"bbb\",\"label\":[[[49],[50]],[[50],[51]]]}" 2.rfc4627:encode([{obj,[{"question",<<"bbb">>},{"label",[["1","2"],["2","3"]]}]},{obj,[{"question",<<"bbb">>},{"label",[["1","2"],["2","3"]]}]}] ).   "[{\"question\":\"bbb\",\"label\":[[[49],[50]],[[50],[51]]]},{\"question\":\"bbb\",\"label\":[[[49],[50]],[[50],[51]]]}]". 3.rfc4627:decode( "{\"question\":\"bbb\",\"label\":[[1,2],[2,3]]}" ).   {ok,{obj,[{"question",<<"bbb">>},{"label",[[1,2],[2,3]]}]}, []} 4.{obj,[{"temp",<<"interface">>},         {"serviceUrl",<<"aaa">>},         {"existing",[{obj,[{"a",<<"b">>},{"c",<<"d">>}]}]},  {"questionList",  [{obj,[{"question",<<"111">>},{"key",<<"222">>}]},   {obj,[{"question",<<"333">>},{"key",<<"444">>}]}]}]}.   "{\"temp\":\"interface\", \"serviceUrl\":\"aaa\", \"existing\":[{\"a\":\"b\", \"c\":\"d\"}], \"questionList\":[{\"question\":\"111\", \"key\":\"222\"}, {\"question\":\"333\", \"key\":\"444\"}] }" ```