We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Exception when logout with auto_login=True
**How to reproduce the issue**
Press logout button

**What you expected to happen**
Shows logout.html

**What actually happens**
Exception:
```
    Traceback (most recent call last):
      File "/usr/local/lib/python3.5/dist-packages/tornado/web.py", line 1509, in _execute
        result = method(*self.path_args, **self.path_kwargs)
      File "/usr/local/lib/python3.5/dist-packages/jupyterhub/handlers/login.py", line 23, in get
        self.render('logout.html')
      File "/usr/local/lib/python3.5/dist-packages/tornado/web.py", line 724, in render
        html = self.render_string(template_name, **kwargs)
      File "/usr/local/lib/python3.5/dist-packages/tornado/web.py", line 857, in render_string
        if template_path not in RequestHandler._template_loaders:
    TypeError: unhashable type: 'list'
```

**Share what version of JupyterHub you are using**
Jupyterhub 0.8 with auto_login=True

Running `jupyter troubleshoot` from the command line, if possible, and posting
its output would also be helpful.

```
$PATH:
	/usr/local/bin
	/usr/local/sbin
	/usr/local/bin
	/usr/sbin
	/usr/bin
	/sbin
	/bin

sys.path:
	/usr/local/bin
	/srv/jupyterhub
	/usr/lib/python35.zip
	/usr/lib/python3.5
	/usr/lib/python3.5/plat-x86_64-linux-gnu
	/usr/lib/python3.5/lib-dynload
	/usr/local/lib/python3.5/dist-packages
	/usr/lib/python3/dist-packages

sys.executable:
	/usr/bin/python3

sys.version:
	3.5.3 (default, Jan 19 2017, 14:11:04)
	[GCC 6.3.0 20170118]

platform.platform():
	Linux-4.4.52+-x86_64-with-Ubuntu-17.04-zesty

which -a jupyter:
	/usr/local/bin/jupyter
	/usr/local/bin/jupyter
```


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `jupyterhub/handlers/login.py`
Content:
```
1 """HTTP Handlers for the hub server"""
2 
3 # Copyright (c) Jupyter Development Team.
4 # Distributed under the terms of the Modified BSD License.
5 
6 from tornado.escape import url_escape
7 from tornado import gen
8 from tornado.httputil import url_concat
9 from tornado import web
10 
11 from .base import BaseHandler
12 
13 
14 class LogoutHandler(BaseHandler):
15     """Log a user out by clearing their login cookie."""
16     def get(self):
17         user = self.get_current_user()
18         if user:
19             self.log.info("User logged out: %s", user.name)
20             self.clear_login_cookie()
21             self.statsd.incr('logout')
22         if self.authenticator.auto_login:
23             self.render('logout.html')
24         else:
25             self.redirect(self.settings['login_url'], permanent=False)
26 
27 
28 class LoginHandler(BaseHandler):
29     """Render the login page."""
30 
31     def _render(self, login_error=None, username=None):
32         return self.render_template('login.html',
33                 next=url_escape(self.get_argument('next', default='')),
34                 username=username,
35                 login_error=login_error,
36                 custom_html=self.authenticator.custom_html,
37                 login_url=self.settings['login_url'],
38                 authenticator_login_url=url_concat(
39                     self.authenticator.login_url(self.hub.base_url),
40                     {'next': self.get_argument('next', '')},
41                 ),
42         )
43 
44     @gen.coroutine
45     def get(self):
46         self.statsd.incr('login.request')
47         user = self.get_current_user()
48         if user:
49             # set new login cookie
50             # because single-user cookie may have been cleared or incorrect
51             self.set_login_cookie(self.get_current_user())
52             self.redirect(self.get_next_url(user), permanent=False)
53         else:
54             if self.authenticator.auto_login:
55                 auto_login_url = self.authenticator.login_url(self.hub.base_url)
56                 if auto_login_url == self.settings['login_url']:
57                     # auto_login without a custom login handler
58                     # means that auth info is already in the request
59                     # (e.g. REMOTE_USER header)
60                     user = yield self.login_user()
61                     if user is None:
62                         # auto_login failed, just 403
63                         raise web.HTTPError(403)
64                     else:
65                         self.redirect(self.get_next_url(user))
66                 else:
67                     if self.get_argument('next', default=False):
68                         auto_login_url = url_concat(auto_login_url, {'next': self.get_next_url()})
69                     self.redirect(auto_login_url)
70                 return
71             username = self.get_argument('username', default='')
72             self.finish(self._render(username=username))
73 
74     @gen.coroutine
75     def post(self):
76         # parse the arguments dict
77         data = {}
78         for arg in self.request.arguments:
79             data[arg] = self.get_argument(arg, strip=False)
80 
81         auth_timer = self.statsd.timer('login.authenticate').start()
82         user = yield self.login_user(data)
83         auth_timer.stop(send=False)
84 
85         if user:
86             already_running = False
87             if user.spawner.ready:
88                 status = yield user.spawner.poll()
89                 already_running = (status is None)
90             if not already_running and not user.spawner.options_form \
91                     and not user.spawner.pending:
92                 # logging in triggers spawn
93                 yield self.spawn_single_user(user)
94             self.redirect(self.get_next_url())
95         else:
96             html = self._render(
97                 login_error='Invalid username or password',
98                 username=data['username'],
99             )
100             self.finish(html)
101 
102 
103 # /login renders the login page or the "Login with..." link,
104 # so it should always be registered.
105 # /logout clears cookies.
106 default_handlers = [
107     (r"/login", LoginHandler),
108     (r"/logout", LogoutHandler),
109 ]
110
```
--- 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/jupyterhub/handlers/login.py b/jupyterhub/handlers/login.py
--- a/jupyterhub/handlers/login.py
+++ b/jupyterhub/handlers/login.py
@@ -20,7 +20,7 @@
             self.clear_login_cookie()
             self.statsd.incr('logout')
         if self.authenticator.auto_login:
-            self.render('logout.html')
+            self.render_template('logout.html')
         else:
             self.redirect(self.settings['login_url'], permanent=False)

{"golden_diff": "diff --git a/jupyterhub/handlers/login.py b/jupyterhub/handlers/login.py\n--- a/jupyterhub/handlers/login.py\n+++ b/jupyterhub/handlers/login.py\n@@ -20,7 +20,7 @@\n             self.clear_login_cookie()\n             self.statsd.incr('logout')\n         if self.authenticator.auto_login:\n-            self.render('logout.html')\n+            self.render_template('logout.html')\n         else:\n             self.redirect(self.settings['login_url'], permanent=False)\n", "issue": "Exception when logout with auto_login=True\n**How to reproduce the issue**\r\nPress logout button\r\n\r\n**What you expected to happen**\r\nShows logout.html\r\n\r\n**What actually happens**\r\nException:\r\n```\r\n    Traceback (most recent call last):\r\n      File \"/usr/local/lib/python3.5/dist-packages/tornado/web.py\", line 1509, in _execute\r\n        result = method(*self.path_args, **self.path_kwargs)\r\n      File \"/usr/local/lib/python3.5/dist-packages/jupyterhub/handlers/login.py\", line 23, in get\r\n        self.render('logout.html')\r\n      File \"/usr/local/lib/python3.5/dist-packages/tornado/web.py\", line 724, in render\r\n        html = self.render_string(template_name, **kwargs)\r\n      File \"/usr/local/lib/python3.5/dist-packages/tornado/web.py\", line 857, in render_string\r\n        if template_path not in RequestHandler._template_loaders:\r\n    TypeError: unhashable type: 'list'\r\n```\r\n\r\n**Share what version of JupyterHub you are using**\r\nJupyterhub 0.8 with auto_login=True\r\n\r\nRunning `jupyter troubleshoot` from the command line, if possible, and posting\r\nits output would also be helpful.\r\n\r\n```\r\n$PATH:\r\n\t/usr/local/bin\r\n\t/usr/local/sbin\r\n\t/usr/local/bin\r\n\t/usr/sbin\r\n\t/usr/bin\r\n\t/sbin\r\n\t/bin\r\n\r\nsys.path:\r\n\t/usr/local/bin\r\n\t/srv/jupyterhub\r\n\t/usr/lib/python35.zip\r\n\t/usr/lib/python3.5\r\n\t/usr/lib/python3.5/plat-x86_64-linux-gnu\r\n\t/usr/lib/python3.5/lib-dynload\r\n\t/usr/local/lib/python3.5/dist-packages\r\n\t/usr/lib/python3/dist-packages\r\n\r\nsys.executable:\r\n\t/usr/bin/python3\r\n\r\nsys.version:\r\n\t3.5.3 (default, Jan 19 2017, 14:11:04)\r\n\t[GCC 6.3.0 20170118]\r\n\r\nplatform.platform():\r\n\tLinux-4.4.52+-x86_64-with-Ubuntu-17.04-zesty\r\n\r\nwhich -a jupyter:\r\n\t/usr/local/bin/jupyter\r\n\t/usr/local/bin/jupyter\r\n```\r\n\n", "before_files": [{"content": "\"\"\"HTTP Handlers for the hub server\"\"\"\n\n# Copyright (c) Jupyter Development Team.\n# Distributed under the terms of the Modified BSD License.\n\nfrom tornado.escape import url_escape\nfrom tornado import gen\nfrom tornado.httputil import url_concat\nfrom tornado import web\n\nfrom .base import BaseHandler\n\n\nclass LogoutHandler(BaseHandler):\n    \"\"\"Log a user out by clearing their login cookie.\"\"\"\n    def get(self):\n        user = self.get_current_user()\n        if user:\n            self.log.info(\"User logged out: %s\", user.name)\n            self.clear_login_cookie()\n            self.statsd.incr('logout')\n        if self.authenticator.auto_login:\n            self.render('logout.html')\n        else:\n            self.redirect(self.settings['login_url'], permanent=False)\n\n\nclass LoginHandler(BaseHandler):\n    \"\"\"Render the login page.\"\"\"\n\n    def _render(self, login_error=None, username=None):\n        return self.render_template('login.html',\n                next=url_escape(self.get_argument('next', default='')),\n                username=username,\n                login_error=login_error,\n                custom_html=self.authenticator.custom_html,\n                login_url=self.settings['login_url'],\n                authenticator_login_url=url_concat(\n                    self.authenticator.login_url(self.hub.base_url),\n                    {'next': self.get_argument('next', '')},\n                ),\n        )\n\n    @gen.coroutine\n    def get(self):\n        self.statsd.incr('login.request')\n        user = self.get_current_user()\n        if user:\n            # set new login cookie\n            # because single-user cookie may have been cleared or incorrect\n            self.set_login_cookie(self.get_current_user())\n            self.redirect(self.get_next_url(user), permanent=False)\n        else:\n            if self.authenticator.auto_login:\n                auto_login_url = self.authenticator.login_url(self.hub.base_url)\n                if auto_login_url == self.settings['login_url']:\n                    # auto_login without a custom login handler\n                    # means that auth info is already in the request\n                    # (e.g. REMOTE_USER header)\n                    user = yield self.login_user()\n                    if user is None:\n                        # auto_login failed, just 403\n                        raise web.HTTPError(403)\n                    else:\n                        self.redirect(self.get_next_url(user))\n                else:\n                    if self.get_argument('next', default=False):\n                        auto_login_url = url_concat(auto_login_url, {'next': self.get_next_url()})\n                    self.redirect(auto_login_url)\n                return\n            username = self.get_argument('username', default='')\n            self.finish(self._render(username=username))\n\n    @gen.coroutine\n    def post(self):\n        # parse the arguments dict\n        data = {}\n        for arg in self.request.arguments:\n            data[arg] = self.get_argument(arg, strip=False)\n\n        auth_timer = self.statsd.timer('login.authenticate').start()\n        user = yield self.login_user(data)\n        auth_timer.stop(send=False)\n\n        if user:\n            already_running = False\n            if user.spawner.ready:\n                status = yield user.spawner.poll()\n                already_running = (status is None)\n            if not already_running and not user.spawner.options_form \\\n                    and not user.spawner.pending:\n                # logging in triggers spawn\n                yield self.spawn_single_user(user)\n            self.redirect(self.get_next_url())\n        else:\n            html = self._render(\n                login_error='Invalid username or password',\n                username=data['username'],\n            )\n            self.finish(html)\n\n\n# /login renders the login page or the \"Login with...\" link,\n# so it should always be registered.\n# /logout clears cookies.\ndefault_handlers = [\n    (r\"/login\", LoginHandler),\n    (r\"/logout\", LogoutHandler),\n]\n", "path": "jupyterhub/handlers/login.py"}], "after_files": [{"content": "\"\"\"HTTP Handlers for the hub server\"\"\"\n\n# Copyright (c) Jupyter Development Team.\n# Distributed under the terms of the Modified BSD License.\n\nfrom tornado.escape import url_escape\nfrom tornado import gen\nfrom tornado.httputil import url_concat\nfrom tornado import web\n\nfrom .base import BaseHandler\n\n\nclass LogoutHandler(BaseHandler):\n    \"\"\"Log a user out by clearing their login cookie.\"\"\"\n    def get(self):\n        user = self.get_current_user()\n        if user:\n            self.log.info(\"User logged out: %s\", user.name)\n            self.clear_login_cookie()\n            self.statsd.incr('logout')\n        if self.authenticator.auto_login:\n            self.render_template('logout.html')\n        else:\n            self.redirect(self.settings['login_url'], permanent=False)\n\n\nclass LoginHandler(BaseHandler):\n    \"\"\"Render the login page.\"\"\"\n\n    def _render(self, login_error=None, username=None):\n        return self.render_template('login.html',\n                next=url_escape(self.get_argument('next', default='')),\n                username=username,\n                login_error=login_error,\n                custom_html=self.authenticator.custom_html,\n                login_url=self.settings['login_url'],\n                authenticator_login_url=url_concat(\n                    self.authenticator.login_url(self.hub.base_url),\n                    {'next': self.get_argument('next', '')},\n                ),\n        )\n\n    @gen.coroutine\n    def get(self):\n        self.statsd.incr('login.request')\n        user = self.get_current_user()\n        if user:\n            # set new login cookie\n            # because single-user cookie may have been cleared or incorrect\n            self.set_login_cookie(self.get_current_user())\n            self.redirect(self.get_next_url(user), permanent=False)\n        else:\n            if self.authenticator.auto_login:\n                auto_login_url = self.authenticator.login_url(self.hub.base_url)\n                if auto_login_url == self.settings['login_url']:\n                    # auto_login without a custom login handler\n                    # means that auth info is already in the request\n                    # (e.g. REMOTE_USER header)\n                    user = yield self.login_user()\n                    if user is None:\n                        # auto_login failed, just 403\n                        raise web.HTTPError(403)\n                    else:\n                        self.redirect(self.get_next_url(user))\n                else:\n                    if self.get_argument('next', default=False):\n                        auto_login_url = url_concat(auto_login_url, {'next': self.get_next_url()})\n                    self.redirect(auto_login_url)\n                return\n            username = self.get_argument('username', default='')\n            self.finish(self._render(username=username))\n\n    @gen.coroutine\n    def post(self):\n        # parse the arguments dict\n        data = {}\n        for arg in self.request.arguments:\n            data[arg] = self.get_argument(arg, strip=False)\n\n        auth_timer = self.statsd.timer('login.authenticate').start()\n        user = yield self.login_user(data)\n        auth_timer.stop(send=False)\n\n        if user:\n            already_running = False\n            if user.spawner.ready:\n                status = yield user.spawner.poll()\n                already_running = (status is None)\n            if not already_running and not user.spawner.options_form \\\n                    and not user.spawner.pending:\n                # logging in triggers spawn\n                yield self.spawn_single_user(user)\n            self.redirect(self.get_next_url())\n        else:\n            html = self._render(\n                login_error='Invalid username or password',\n                username=data['username'],\n            )\n            self.finish(html)\n\n\n# /login renders the login page or the \"Login with...\" link,\n# so it should always be registered.\n# /logout clears cookies.\ndefault_handlers = [\n    (r\"/login\", LoginHandler),\n    (r\"/logout\", LogoutHandler),\n]\n", "path": "jupyterhub/handlers/login.py"}]}