From 6cf5f9d05f430df15a3d2d2dd901b3de3ad099b4 Mon Sep 17 00:00:00 2001
From: Peter Burns <rictic@google.com>
Date: Mon, 20 Aug 2018 10:24:34 -0700
Subject: [PATCH] The return type of mixinBehaviors is unknown

It's more than just the input class. Leaving it unknown allows the user to add annotations like:

```
 * @constructor
 * @extends {Polymer.Element}
 * @implements {IronValidatableBehaviorInterface}
```
---
 lib/legacy/class.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/legacy/class.js b/lib/legacy/class.js
index a7bde03aac..fcd4db52c6 100644
--- a/lib/legacy/class.js
+++ b/lib/legacy/class.js
@@ -33,7 +33,7 @@ let metaProps = {
  * @template T
  * @param {!Object|!Array<!Object>} behaviors Behavior object or array of behaviors.
  * @param {function(new:T)} klass Element class.
- * @return {function(new:T)} Returns a new Element class extended by the
+ * @return {?} Returns a new Element class extended by the
  * passed in `behaviors` and also by `LegacyElementMixin`.
  * @suppress {invalidCasts, checkTypes}
  */