ken</span><span class="RktPn">)</span><span class="hspace">&nbsp;</span>&rarr;<span class="hspace">&nbsp;</span><span class="RktSym"><a href="file:///Applications/Racket%20v6.4/doc/reference/void.html#%28def._%28%28quote._~23~25kernel%29._void~3f%29%29" class="RktValLink" data-pltdoc="x">void?</a></span></p></blockquote></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">token</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym"><a href="