convert a list of booleans to string
<p>How do I convert this:</p>

<pre><code>[True, True, False, True, True, False, True]
</code></pre>

<p>Into this:</p>

<pre><code>'AB DE G'
</code></pre>

<p>Note: C and F are missing in the output because the corresponding items in the input list are False.</p>
