</span></code></pre></div>
    </div>

    <div id="arguments">
    <h2>Arguments</h2>
    <dl><dt>date_prod</dt>
<dd><p>A vector of class <code>character</code> or <code>Date</code>, in the
format "yyyy-mm-dd", indicating the date of production of a unit.
Use <code>NA</code> for missing elements.</p></dd>
<dt>date_register</dt>
<dd><p>A vector of class <code>character</code> or <code>Date</code>, in
the format "yyyy-mm-dd", indicating the date of registration of a unit.
Use <code>NA</code> for 