scope issues. $replyValue on line 4 is null, when it should be a 1 or a 0

doesntwork.php

public function markMessagesRead($mysqli, $replyValue){
  $allMessages = $this->getAllMessages($mysqli);
  $replyCheck = function ($message){
    return $message.getAttribute($mysqli, "reply", "Reply") == $replyValue;
  };
  foreach(array_filter($allMessages, $replyCheck) as $messageItem){
    $messageItem->setFirstViewDate($mysqli);
  }
}