s="r-in"><span><span class="op">)</span></span></span>
<span class="r-out co"><span class="r-pr">#&gt;</span> [1] "283957200s (~9 years)"  "347122800s (~11 years)" "126172800s (~4 years)" </span>
<span class="r-out co"><span class="r-pr">#&gt;</span> [4] "347122800s (~11 years)" "378662400s (~12 years)"</span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="co"># Mixed date classes -&gt; durations</span></span></span>
<span class="r-in"><span><span class="fu">calc_duration</spa