function global_notice_meta_box() {      $screens = array( 'post', 'page', 'book' );      foreach ( $screens as $screen ) {         add_meta_box(             'global-notice',             __( 'Global Notice', 'sitepoint' ),             'global_notice_meta_box_callback',             $screen         );     } }  add_action( 'add_meta_boxes', 'global_notice_meta_box' ); 

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