t : bytes -&gt; int -&gt; char -&gt; int option</pre><div class="info ">
<div class="info-desc">
<p><code class="code">index_from_opt&nbsp;s&nbsp;i&nbsp;c</code> returns the index of the first occurrence of
    byte <code class="code">c</code> in <code class="code">s</code> after position <code class="code">i</code> or <code class="code">None</code> if <code class="code">c</code> does not occur in <code class="code">s</code>
    after position <code class="code">i</code>.
    <code class="code">index_opt&nb