Adding a color to note woocommerce

I want to add color to a private note inside woocommerce trough a class simular to the the customer-note. I tried adding a new case switch-case statement like the example below, but this didn’t work for me.

case 'Private.':
  $note_classes[] = 'private-note';
  return $note_classes;
  break;

The customer note is being added like this:

default:
  return get_comment_meta( $note->comment_ID, 'is_customer_note', true ) ? array( 'customer-note', 'note' ) : array( 'note' );
  break;

Is it possible to detect the type of note and add a class to this note which I can use to add colors?