_start</span>, <span class='va'>event_end</span><span class='op'>)</span></pre>

    <h2 class="hasAnchor" id="arguments"><a class="anchor" href="#arguments"></a>Arguments</h2>
    <table class="ref-arguments">
    <colgroup><col class="name" /><col class="desc" /></colgroup>
    <tr>
      <th>list_of_returns</th>
      <td><p>a list of objects of S3 class <code>returns</code>, each
element of which is treated as a security.</p></td>
    </tr>
    <tr>
      <th>event_start</th>
      <td><p>an object of <