Deprecated: Return type of B::jsonSerialize() should either be compatible with JsonSerializable::jsonSerialize(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /in/Ldd3X on line 4
string(53) "{"Recursion":{"across":{"multiple":{"levels":null}}}}"
Notice: Use of undefined constant JSON_PARTIAL_OUTPUT_ON_ERROR - assumed 'JSON_PARTIAL_OUTPUT_ON_ERROR' in /in/Ldd3X on line 16
Warning: json_encode() expects parameter 2 to be long, string given in /in/Ldd3X on line 16
NULL