trying to figure out how to dynamically expand puppet service resource subscriptions - this code compiles but is it correct/will it work?

gistfile1.txt

 if $imagemagick_php {
        $phpimagick = 'pecl-imagick'
 } else {
        $phpimagick = '' 
 }

 $phpfpmsub = [ File['/etc/php/fpm-php5.3/php-fpm.conf','/etc/php/fpm-php5.3/php.ini'], Package['php',$phpimagick], ]

 service {"php-fpm":
   name      => "php-fpm",
   enable    => "true",
   ensure    => "running",
   hasstatus => "true",
   subscribe => $phpfpmsub,
 }

if $imagemagick_php {
        $phpimagick = 'pecl-imagick'
 } else {
        $phpimagick = undef
 }

 $phpfpmsub = [ File['/etc/php/fpm-php5.3/php-fpm.conf','/etc/php/fpm-php5.3/php.ini'], Package['php',$phpimagick], ]

 service {"php-fpm":
   name      => "php-fpm",
   enable    => "true",
   ensure    => "running",
   hasstatus => "true",
   subscribe => $phpfpmsub,
 }