>
<li><code class="code">+</code>: for signed numerical conversions, prefix number with a <code class="code">+</code>
     sign if positive.</li>
<li>space: for signed numerical conversions, prefix number with a
     space if positive.</li>
<li><code class="code"><span class="keywordsign">#</span></code>: request an alternate formatting style for the hexadecimal
     and octal integer types (<code class="code">x</code>, <code class="code"><span class="constructor">X</span></code>, <code class="code">o</code