diff --git a/src/lib/gevent_ws/__init__.py b/src/lib/gevent_ws/__init__.py
index 76564054..a157e94c 100644
--- a/src/lib/gevent_ws/__init__.py
+++ b/src/lib/gevent_ws/__init__.py
@@ -262,6 +262,8 @@ class WebSocketHandler(WSGIHandler):
 
     def process_result(self):
         if "wsgi.websocket" in self.environ:
+            if self.result is None:
+                return
             # Flushing result is required for werkzeug compatibility
             for elem in self.result:
                 pass