unique $keys array when add custom key from Several places with postmeta_form_keys

[myousefi08]

I added two similar custom key from my theme and a plugin with postmeta_form_keys filter.
but now display both of theme in custom-fields name's select box (custom-fields metabox - post.php or post-new.php)
I think is better to unique $keys before options are printed.

wp-admin/includes/template.php
line ~730

before:
foreach ( $keys as $key ) {

after:
$keys = array_unique($keys);
foreach ( $keys as $key ) {