code: public function convert(Stmt\Unset_ $node)
      {
          $unset = '';
          foreach ($node->vars as $var) {
          	if ($var instanceof Expr\Variable) {
          		$unset .= 'let '.$this->dispatcher->p($var).' = null;'."\n";
          	} else {
              	$unset .= 'unset '.$this->dispatcher->p($var).';'."\n";
          	}
          }
  
          return $unset;
      }
docs: @param Stmt\Unset_ $node
  
  @return string