diff --git a/lib/core.js b/lib/core.js
index <HASH>..<HASH> 100644
--- a/lib/core.js
+++ b/lib/core.js
@@ -373,9 +373,8 @@ function keyObj(key) {
 	return obj;
 }
 
-function normalizeList(arr) {
-	if (!Array.isArray(arr)) arr = arr.split(',');
-	return arr.map(function(str) {return str.trim();}).sort().join(',');
+function normalizeList(strlist) {
+	return strlist.split(',').map(function(str) {return str.trim();}).sort().join(',');
 }
 
 function dataEqual(a, b) {
Don't let express manage a http header list