title: How to give subtitles for subplot in plot_ly using R
body: <p>I am wondering how to give difference subtitles for the subplots using plot_ly. Any hint please. I got one title BB in this case. Thanks.</p>
  
  <pre><code>p &lt;- subplot(
        plot_ly(economics, x = date, y = uempmed)%&gt;%layout(showlegend = FALSE, title="AA"),
        plot_ly(economics, x = date, y = unemploy)%&gt;%layout(showlegend = FALSE, title="BB"),
  margin = 0.05
  ) 
  </code></pre>