><strong><code>transform</code>:</strong>  A closure that accepts an element of this
  sequence as its argument and returns a sequence or collection.
<strong>Returns:</strong> The resulting flattened array.</p>

<p><strong>Complexity:</strong> O(<em>m</em> + <em>n</em>), where <em>m</em> is the length of this sequence
  and <em>n</em> is the length of the result.
<strong>See Also:</strong> <code>joined()</code>, <code>map(_:)</code></p>

    <h4>Declaration</h4>    
    <code class="language-swift">func fla