Php-is there a problem with this code? Why doesn't my call function react?

Php

function Genvericode ($type, $length =4, $clear =true) {
$nums =range (0,9); Array of numbers
$lower =range (' A ', ' Z '); Small Letter Array
$upper =range (' A ', ' Z '); Uppercase Array
$ignore =array (' 0 ', ' o ', ' o ', ' 1 ', ' l ', ' I ', ' 9 ', ' Q '); Hard-to-recognize character array

$chars=array();if($type==1)    $chars=$nums; // 只需要数字数组elseif($type==2)    $chars=array_merge($nums,$lower); // 数字+小写字母elseif($type==3)    $chars=array_merge($nums,$lower,$upper); // 数字+小写字母+大写字母if($clear)    $chars=array_diff($chars,$ignore); // 排除难辨认字符$keys=array_rand($chars,$length); // 随机取出length个字符，返回它们的key$code="";foreach($keys as $key)    $code.=$chars[$key]; // 通过key可以去$chars中找到具体的值，并在循环中拼接起来return $code;

}
Why did I call no response?

