/a></span><span class='op'>(</span><span class='va'>example1</span>,
  TITLE <span class='op'>=</span> <span class='op'>~</span> <span class='st'>"This is my title;"</span>,
  MODEL <span class='op'>=</span> <span class='op'>~</span> <span class='va'>.</span> <span class='op'>+</span> <span class='st'>"\nmpg ON hp;"</span>,
  usevariables <span class='op'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/c.html'>c</a></span><span class='op'>(</span><span class='st'>"mpg"</span>, <span class='st'>"hp