> <span class="cn">NULL</span>,</span>
<span>  from <span class="op">=</span> <span class="cn">NULL</span>,</span>
<span>  to <span class="op">=</span> <span class="cn">NULL</span>,</span>
<span>  by <span class="op">=</span> <span class="st">"day"</span>,</span>
<span>  engine <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"loess"</span>, <span class="st">"locfit"</span><span class="op">)</span>,