="r-out co"><span class="r-pr">#&gt;</span> [1] "Next class is D"</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> [1] "Calling class D `foo` method"</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> [1] "Self is a"</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> [1] "Next class is F"</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> [1] "Calling class F `foo` method"</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> [1] "Self is a"</span>
<span