title: Accessing nested objects within objects in PHP not working
body: <p>In PHP, I'm requesting data from my QuickBooks Online account using their Query functions.</p>
  
  <p>I'm iterating through each customer object that is returned in a standard foreach($customer as $x) code block.</p>
  
  <p>Using var_dump, I can tell each object has the following format:</p>
  
  <pre><code>object(QuickBooksOnline\API\Data\IPPCustomer) [34]
  public 'Taxable' =&gt; string 'true' (length=4)
  public 'BillAddr' =&gt;
      object(QuickBooksOnline\API\Data\IPPCustomer) [78]
      public 'Id' =&gt; string '7509' (length=4)
      public 'Line1' =&gt; '1234 Irrelevant Dr.' (length=19)
  </code></pre>
  
  <p>In PHP, if I simply try to access $x->Taxable, it works no problem, but <em>any</em> sub-object I try to access returns an error: "trying to get property of non-object on line X"</p>
  
  <p>So:</p>
  
  <pre><code>echo $x-&gt;Taxable; 
  </code></pre>
  
  <p>gives me the taxable status, but</p>
  
  <pre><code>echo $x-&gt;BillAddr-&gt;Line1; 
  </code></pre>
  
  <p>gives me an error.</p>
  
  <p>These are public classes, so shouldn't I be able to call them like this? </p>