nbsp;len</code> returns a new byte sequence of length <code class="code">len</code>,
    containing the subsequence of <code class="code">s</code> that starts at position <code class="code">start</code>
    and has length <code class="code">len</code>.</p>

<p>Raise <code class="code"><span class="constructor">Invalid_argument</span></code> if <code class="code">start</code> and <code class="code">len</code> do not designate a
    valid range of <code class="code">s</code>.</p>
</div>
</div>

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