We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
__flush__ produces an HTML reponse 
The response for the flush endpoint is a raw HTML response from Pyramid. I suggest make it a JSON response for compatibility with the rest of the API. Maybe return `{}`?

```
gsurita-30820:kinto gsurita$ http post http://localhost:8888/v1/__flush__
HTTP/1.1 202 Accepted
Content-Length: 157
Content-Type: text/html; charset=UTF-8
Date: Tue, 21 Feb 2017 13:56:56 GMT
Server: waitress
X-Content-Type-Options: nosniff

<html>
 <head>
  <title>202 Accepted</title>
 </head>
 <body>
  <h1>202 Accepted</h1>
  The request is accepted for processing.<br/><br/>



 </body>
</html>
__flush__ produces an HTML reponse 
The response for the flush endpoint is a raw HTML response from Pyramid. I suggest make it a JSON response for compatibility with the rest of the API. Maybe return `{}`?

```
gsurita-30820:kinto gsurita$ http post http://localhost:8888/v1/__flush__
HTTP/1.1 202 Accepted
Content-Length: 157
Content-Type: text/html; charset=UTF-8
Date: Tue, 21 Feb 2017 13:56:56 GMT
Server: waitress
X-Content-Type-Options: nosniff

<html>
 <head>
  <title>202 Accepted</title>
 </head>
 <body>
  <h1>202 Accepted</h1>
  The request is accepted for processing.<br/><br/>



 </body>
</html>

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `kinto/views/flush.py`
Content:
```
1 from cornice import Service
2 from pyramid import httpexceptions
3 from pyramid.security import NO_PERMISSION_REQUIRED
4 
5 from kinto.events import ServerFlushed
6 
7 flush = Service(name='flush',
8                 description='Clear database content',
9                 path='/__flush__')
10 
11 
12 @flush.post(permission=NO_PERMISSION_REQUIRED)
13 def flush_post(request):
14     request.registry.storage.flush()
15     request.registry.permission.flush()
16     request.registry.cache.flush()
17     event = ServerFlushed(request)
18     request.registry.notify(event)
19     return httpexceptions.HTTPAccepted()
20
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/kinto/views/flush.py b/kinto/views/flush.py
--- a/kinto/views/flush.py
+++ b/kinto/views/flush.py
@@ -1,5 +1,4 @@
 from cornice import Service
-from pyramid import httpexceptions
 from pyramid.security import NO_PERMISSION_REQUIRED
 
 from kinto.events import ServerFlushed
@@ -16,4 +15,6 @@
     request.registry.cache.flush()
     event = ServerFlushed(request)
     request.registry.notify(event)
-    return httpexceptions.HTTPAccepted()
+
+    request.response.status = 202
+    return {}

{"golden_diff": "diff --git a/kinto/views/flush.py b/kinto/views/flush.py\n--- a/kinto/views/flush.py\n+++ b/kinto/views/flush.py\n@@ -1,5 +1,4 @@\n from cornice import Service\n-from pyramid import httpexceptions\n from pyramid.security import NO_PERMISSION_REQUIRED\n \n from kinto.events import ServerFlushed\n@@ -16,4 +15,6 @@\n     request.registry.cache.flush()\n     event = ServerFlushed(request)\n     request.registry.notify(event)\n-    return httpexceptions.HTTPAccepted()\n+\n+    request.response.status = 202\n+    return {}\n", "issue": "__flush__ produces an HTML reponse \nThe response for the flush endpoint is a raw HTML response from Pyramid. I suggest make it a JSON response for compatibility with the rest of the API. Maybe return `{}`?\r\n\r\n```\r\ngsurita-30820:kinto gsurita$ http post http://localhost:8888/v1/__flush__\r\nHTTP/1.1 202 Accepted\r\nContent-Length: 157\r\nContent-Type: text/html; charset=UTF-8\r\nDate: Tue, 21 Feb 2017 13:56:56 GMT\r\nServer: waitress\r\nX-Content-Type-Options: nosniff\r\n\r\n<html>\r\n <head>\r\n  <title>202 Accepted</title>\r\n </head>\r\n <body>\r\n  <h1>202 Accepted</h1>\r\n  The request is accepted for processing.<br/><br/>\r\n\r\n\r\n\r\n </body>\r\n</html>\n__flush__ produces an HTML reponse \nThe response for the flush endpoint is a raw HTML response from Pyramid. I suggest make it a JSON response for compatibility with the rest of the API. Maybe return `{}`?\r\n\r\n```\r\ngsurita-30820:kinto gsurita$ http post http://localhost:8888/v1/__flush__\r\nHTTP/1.1 202 Accepted\r\nContent-Length: 157\r\nContent-Type: text/html; charset=UTF-8\r\nDate: Tue, 21 Feb 2017 13:56:56 GMT\r\nServer: waitress\r\nX-Content-Type-Options: nosniff\r\n\r\n<html>\r\n <head>\r\n  <title>202 Accepted</title>\r\n </head>\r\n <body>\r\n  <h1>202 Accepted</h1>\r\n  The request is accepted for processing.<br/><br/>\r\n\r\n\r\n\r\n </body>\r\n</html>\n", "before_files": [{"content": "from cornice import Service\nfrom pyramid import httpexceptions\nfrom pyramid.security import NO_PERMISSION_REQUIRED\n\nfrom kinto.events import ServerFlushed\n\nflush = Service(name='flush',\n                description='Clear database content',\n                path='/__flush__')\n\n\n@flush.post(permission=NO_PERMISSION_REQUIRED)\ndef flush_post(request):\n    request.registry.storage.flush()\n    request.registry.permission.flush()\n    request.registry.cache.flush()\n    event = ServerFlushed(request)\n    request.registry.notify(event)\n    return httpexceptions.HTTPAccepted()\n", "path": "kinto/views/flush.py"}], "after_files": [{"content": "from cornice import Service\nfrom pyramid.security import NO_PERMISSION_REQUIRED\n\nfrom kinto.events import ServerFlushed\n\nflush = Service(name='flush',\n                description='Clear database content',\n                path='/__flush__')\n\n\n@flush.post(permission=NO_PERMISSION_REQUIRED)\ndef flush_post(request):\n    request.registry.storage.flush()\n    request.registry.permission.flush()\n    request.registry.cache.flush()\n    event = ServerFlushed(request)\n    request.registry.notify(event)\n\n    request.response.status = 202\n    return {}\n", "path": "kinto/views/flush.py"}]}