cpanel xml api php注意事项

我收到以下通知

Notice: Use of undefined constant username - assumed 'username'

........

以及生成它的代码

$acct = array(username => $username, password => $password, domain => $domain);

我在这里做错了什么。最初的代码是这样的

$acct = array( username => "someuser", password => "pass123", domain => "thisdomain.com");

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谢谢。

试着引用钥匙，就像这样：

$acct = array('username' => $username, 'password' => $password, 'domain' => $domain);