 <code class="computeroutput"><span class="identifier">make_dense_output</span></code> you
        need to specialize two class templates. Suppose your steppers are called
        <code class="computeroutput"><span class="identifier">custom_stepper</span></code>, <code class="computeroutput"><span class="identifier">custom_controller</span></code> and <code class="computeroutput"><span class="identifier">custom_dense_output</span></code>.
        Then, the first class you need to specialize is <code class="