From: Benjamin Drung <benjamin.drung@cloud.ionos.com>
Date: Thu, 15 Nov 2018 16:18:51 +0100
Subject: [PATCH] Add support for Python 3.7

---
 tornado/gen.py               | 3 +--
 tornado/queues.py            | 1 -
 tornado/test/asyncio_test.py | 3 ++-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/tornado/gen.py b/tornado/gen.py
index 99f9106..bdb32ff 100644
--- a/tornado/gen.py
+++ b/tornado/gen.py
@@ -482,9 +482,8 @@ class WaitIterator(object):
         self.current_future = done
         self.current_index = self._unfinished.pop(done)
 
-    @coroutine
     def __aiter__(self):
-        raise Return(self)
+        return self
 
     def __anext__(self):
         if self.done():
diff --git a/tornado/queues.py b/tornado/queues.py
index 0041a80..141c539 100644
--- a/tornado/queues.py
+++ b/tornado/queues.py
@@ -253,7 +253,6 @@ class Queue(object):
         """
         return self._finished.wait(timeout)
 
-    @gen.coroutine
     def __aiter__(self):
         return _QueueIterator(self)
 
diff --git a/tornado/test/asyncio_test.py b/tornado/test/asyncio_test.py
index d0e3f2b..ae9125f 100644
--- a/tornado/test/asyncio_test.py
+++ b/tornado/test/asyncio_test.py
@@ -46,7 +46,8 @@ class AsyncIOLoopTest(AsyncTestCase):
         if hasattr(asyncio, 'ensure_future'):
             ensure_future = asyncio.ensure_future
         else:
-            ensure_future = asyncio.async
+            # async is a reserved word in Python 3.7
+            ensure_future = getattr(asyncio, "async")
 
         x = yield ensure_future(
             asyncio.get_event_loop().run_in_executor(None, lambda: 42))