Drupal Menu Page Callback Function went wrong with arguments I am new to Drupal, and I was trying a small example from Book "Pro Drupal 7 Development", this is an example of basic menu system, here is code:

function menufun_menu() {
$items['menufun'] = array(
    'title' =&gt; 'Greeting',
    'page callback' =&gt; 'menufun_hello',
    'access callback' =&gt; TRUE,
    'type' =&gt; MENU_CALLBACK,
);
return $items;
}

function menufun_hello($first_name = '', $last_name = '') {
return t('Hello, @first_name @last_name'，
    array('@first_name' =&gt; $first_name, '@last_name' =&gt; $last_name));
}


But I got HTTP 500 Error all the time: 


  The website encountered an error while retrieving 'http://example.com/SampleDrupalSite/'. It may be down for maintenance or configured incorrectly.
  Here are some suggestions:
  Reload this webpage later.
  HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.


When I tried function menufun_hello() without page callback arguments, it was all okay. Here is code without parameters: 

    function menufun_hello() {
    return t('Hello!');
    }


May I ask what was wrong with this? (Plus, I've googled before I post it here).
Really embarrassed to say I made one tiny small mistake in this line of code:

return t('Hello, @first_name @last_name'，
array('@first_name' =&gt; $first_name, '@last_name' =&gt; $last_name));


I was typing the first comma while switched to Chinese Simplified PinYin, correct code should be: 

return t('Hello, @first_name @last_name',
array('@first_name' =&gt; $first_name, '@last_name' =&gt; $last_name));


After I changed it, everything is okay now. Thank you all for paying attention to my silly question.