an class="n">registered_patients</span> <span class="o">=</span> <span class="n">recruit_time</span> <span class="o">&lt;=</span> <span class="n">time</span>
        <span class="n">has_failed</span> <span class="o">=</span> <span class="n">time</span> <span class="o">-</span> <span class="n">recruit_time</span><span class="p">[</span><span class="n">registered_patients</span><span class="p">]</span> <span class="o">&gt;</span> <span class="n">event_time</span><span class="p">[</span><span class="n">registe