title: How access array inside of JSON?
body: <p>I'm use Guzzle for Laravel to send POST for Webservice, but I can't access array to send picture. That is the structed to I need follow:</p>
  
  <pre><code>{
  "title": "xxxxxxxxxxxxxxxxx",
  "category_id": "XXXX",
  "official_store_id": null,
  "pictures": [
    {
  "id": "XXXXX",
  "url": "http://mlb-s1-p.mlstatic.com/292325-MLB25432321923_032017-O.jpg",
  "secure_url": "https://mlb-s1-p.mlstatic.com/292325-MLB25432321923_032017-O.jpg",
  "size": "500x500",
  "max_size": "500x500",
  "quality": ""
  }
  ],
  }
  </code></pre>
  
  <p>I try to send it like this:</p>
  
  <pre><code> $r = $client-&gt;request('POST', 'https://api.mercadolibre.com/items?access_token='.$token-&gt;erp_access_token, [
                  'json' =&gt; [
                      'title' =&gt; $name,
                      'category_id' =&gt; $cat2,
                      'price' =&gt; $price,
                      'currency_id' =&gt; 'BRL',
                      'available_quantity' =&gt; $quantity,
                      'buying_mode' =&gt; 'buy_it_now',
                      'listing_type_id' =&gt; 'gold_special',
                      'condition' =&gt; 'new',
                      'description' =&gt; $description,
                      'pictures' =&gt; [
                          'url' =&gt; $image
                      ]
                  ]
              ]);
  </code></pre>
  
  <p>Returns the error: </p>
  
  <pre><code>{"message":"body.invalid_field_types","error":"[invalid property type: [pictures] expected List but was JSONObject value (truncated...)
  </code></pre>
  
  <p>I read the Guzzle docs, but I not found any example for that case. </p>
  
  <p>Any suggestion?</p>