 or counterfactual quantities.
Nested or "complex" counterfactual queries of the form
<code>Y[X=1, M[X=0]]</code> are allowed.</p>
    </div>

    <div class="section level2">
    <h2 id="ref-examples">Examples<a class="anchor" aria-label="anchor" href="#ref-examples"></a></h2>
    <div class="sourceCode"><pre class="sourceCode r"><code><span class="r-in"><span><span class="va">model</span> <span class="op">&lt;-</span> <span class="fu"><a href="make_model.html">make_model</a></span><span class="op">(</span