diff --git a/app/helpers.php b/app/helpers.php
index d9e3c6d2..e3511193 100644
--- a/app/helpers.php
+++ b/app/helpers.php
@@ -245,7 +245,7 @@ if (! function_exists('range_compare')) {
     }
 }
 
-if (! function_exists('single_case')) {
+if (!function_exists('single_case')) {
     /**
     *  将一个字串中含有全角的数字字符、字母、空格或'%+-()'字符转换为相应半角字符
     *