gt;</span> [1] 1</span>
<span class="r-in"><span><span class="va">test</span><span class="op">$</span><span class="fu">del_attr</span><span class="op">(</span><span class="st">"x"</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="va">test</span><span class="op">$</span><span class="va">x</span></span></span>
<span class="r-out co"><span class="r-pr">#&gt;</span> NULL</span>
</code></pre></div>
    </div>
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