PHP/Smarty - checking if a file exists

I have never worked with smarty templates before, but found this cool tip to allow me to check file_exists("file") within the template itself. I wanted to check to see if a specialmsg.tpl file existed, and display the contents of that file if it existed:


{assign var="specialmsg" value="/location/to/specialmsg.tpl"}
{ if file_exists($specialmsg) }
<tr>
<td align="right" class="HeadText">&nbsp;</td>
<td valign="top" align="right" class="HeadText">
{include file="specialmsg.tpl"}</td>
<td align="right" class="HeadText">&nbsp;</td>
</tr>
{/if}


EDIT: added missing quote as mentioned by CJ.