">def</span> <span class="nf">propagate</span><span class="p">(</span>
    <span class="n">s</span><span class="p">:</span> <span class="n">iDEA</span><span class="o">.</span><span class="n">system</span><span class="o">.</span><span class="n">System</span><span class="p">,</span>
    <span class="n">state</span><span class="p">:</span> <span class="n">iDEA</span><span class="o">.</span><span class="n">state</span><span class="o">.</span><span class="n">SingleBodyState</span><span class="p">,</span>
    <sp