Swift NSURL error while creating : <p>This is my code. Error: <code>fatal error: unexpectedly found nil while unwrapping an Optional value
(lldb)</code> I have no idea where;s the problem</p>

<pre><code>res = "https://www.example.com/range.php?arr1=48.15&amp;arr2=48.15&amp;API_KEY=&gt;code"
    let url = NSURL(string: res)! // error line
    print("url craeted" + res)
    return url
</code></pre>
