Handling JSON Invalidity in PHP

It happens that a string with JSON is built incorrectly. In this case, the json_decode function will return null. Let's try it in practice. Let's make invalid JSON (determine for yourself what's wrong with it):

php<?php
  $json = '["a", "b", "c",]';
?>

Let's try to parse this JSON:

php<?php
  $data = json_decode($json);
  var_dump($data); // will output null
?>

Задание 1

Given a string with some JSON. Parse it into a PHP data structure. Output the parsing result or an error if parsing the JSON failed.