diff --git a/src/LZCompressor/LZUtil.php b/src/LZCompressor/LZUtil.php
index a0599b2..affb7be 100644
--- a/src/LZCompressor/LZUtil.php
+++ b/src/LZCompressor/LZUtil.php
@@ -40,7 +40,7 @@ public static function getBaseValue($alphabet, $character)
     public static function fromCharCode()
     {
         return array_reduce(func_get_args(), function ($a, $b) {
-            $a .= self::utf8_chr($b);
+            $a .= LZUtil::utf8_chr($b);
             return $a;
         });
     }
@@ -107,4 +107,4 @@ public static function utf8_charAt($str, $num)
     public static function utf8_strlen($str) {
         return mb_strlen($str, 'UTF-8');
     }
-}
\ No newline at end of file
+}