We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Show return model of sponsor types list in Swagger spec
Currently no return model (or schema) is shown for the GET API to get sponsor types used in a Event

![sponsor_type_old](https://cloud.githubusercontent.com/assets/4047597/16110108/be118070-33c9-11e6-8532-ce104c5a57d3.png)


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `open_event/api/sponsors.py`
Content:
```
1 from flask.ext.restplus import Resource, Namespace
2 
3 from open_event.models.sponsor import Sponsor as SponsorModel
4 
5 from .helpers.helpers import get_paginated_list, requires_auth, get_object_in_event
6 from .helpers.utils import PAGINATED_MODEL, PaginatedResourceBase, ServiceDAO, \
7     PAGE_PARAMS, POST_RESPONSES, PUT_RESPONSES
8 from .helpers import custom_fields as fields
9 
10 api = Namespace('sponsors', description='Sponsors', path='/')
11 
12 SPONSOR = api.model('Sponsor', {
13     'id': fields.Integer(required=True),
14     'name': fields.String(),
15     'url': fields.Uri(),
16     'logo': fields.ImageUri(),
17     'description': fields.String(),
18     'level': fields.String(),
19     'sponsor_type': fields.String(),
20 })
21 
22 SPONSOR_PAGINATED = api.clone('SponsorPaginated', PAGINATED_MODEL, {
23     'results': fields.List(fields.Nested(SPONSOR))
24 })
25 
26 SPONSOR_POST = api.clone('SponsorPost', SPONSOR)
27 del SPONSOR_POST['id']
28 
29 
30 # Create DAO
31 class SponsorDAO(ServiceDAO):
32     def list_types(self, event_id):
33         sponsors = self.list(event_id)
34         return list(set(
35             sponsor.sponsor_type for sponsor in sponsors
36             if sponsor.sponsor_type))
37 
38 
39 DAO = SponsorDAO(SponsorModel, SPONSOR_POST)
40 
41 
42 @api.route('/events/<int:event_id>/sponsors/<int:sponsor_id>')
43 @api.response(404, 'Sponsor not found')
44 @api.response(400, 'Sponsor does not belong to event')
45 class Sponsor(Resource):
46     @api.doc('get_sponsor')
47     @api.marshal_with(SPONSOR)
48     def get(self, event_id, sponsor_id):
49         """Fetch a sponsor given its id"""
50         return DAO.get(event_id, sponsor_id)
51 
52     @requires_auth
53     @api.doc('delete_sponsor')
54     @api.marshal_with(SPONSOR)
55     def delete(self, event_id, sponsor_id):
56         """Delete a sponsor given its id"""
57         return DAO.delete(event_id, sponsor_id)
58 
59     @requires_auth
60     @api.doc('update_sponsor', responses=PUT_RESPONSES)
61     @api.marshal_with(SPONSOR)
62     @api.expect(SPONSOR_POST)
63     def put(self, event_id, sponsor_id):
64         """Update a sponsor given its id"""
65         return DAO.update(event_id, sponsor_id, self.api.payload)
66 
67 
68 @api.route('/events/<int:event_id>/sponsors')
69 class SponsorList(Resource):
70     @api.doc('list_sponsors')
71     @api.marshal_list_with(SPONSOR)
72     def get(self, event_id):
73         """List all sponsors"""
74         return DAO.list(event_id)
75 
76     @requires_auth
77     @api.doc('create_sponsor', responses=POST_RESPONSES)
78     @api.marshal_with(SPONSOR)
79     @api.expect(SPONSOR_POST)
80     def post(self, event_id):
81         """Create a sponsor"""
82         return DAO.create(
83             event_id,
84             self.api.payload,
85             self.api.url_for(self, event_id=event_id)
86         )
87 
88 
89 @api.route('/events/<int:event_id>/sponsors/types')
90 class SponsorTypesList(Resource):
91     @api.doc('list_sponsor_types')
92     def get(self, event_id):
93         """List all sponsor types"""
94         return DAO.list_types(event_id)
95 
96 
97 @api.route('/events/<int:event_id>/sponsors/page')
98 class SponsorListPaginated(Resource, PaginatedResourceBase):
99     @api.doc('list_sponsors_paginated', params=PAGE_PARAMS)
100     @api.marshal_with(SPONSOR_PAGINATED)
101     def get(self, event_id):
102         """List sponsors in a paginated manner"""
103         return get_paginated_list(
104             SponsorModel,
105             self.api.url_for(self, event_id=event_id),
106             args=self.parser.parse_args(),
107             event_id=event_id
108         )
109
```
--- 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/open_event/api/sponsors.py b/open_event/api/sponsors.py
--- a/open_event/api/sponsors.py
+++ b/open_event/api/sponsors.py
@@ -88,7 +88,7 @@
 
 @api.route('/events/<int:event_id>/sponsors/types')
 class SponsorTypesList(Resource):
-    @api.doc('list_sponsor_types')
+    @api.doc('list_sponsor_types', model=[fields.String()])
     def get(self, event_id):
         """List all sponsor types"""
         return DAO.list_types(event_id)

{"golden_diff": "diff --git a/open_event/api/sponsors.py b/open_event/api/sponsors.py\n--- a/open_event/api/sponsors.py\n+++ b/open_event/api/sponsors.py\n@@ -88,7 +88,7 @@\n \n @api.route('/events/<int:event_id>/sponsors/types')\n class SponsorTypesList(Resource):\n-    @api.doc('list_sponsor_types')\n+    @api.doc('list_sponsor_types', model=[fields.String()])\n     def get(self, event_id):\n         \"\"\"List all sponsor types\"\"\"\n         return DAO.list_types(event_id)\n", "issue": "Show return model of sponsor types list in Swagger spec\nCurrently no return model (or schema) is shown for the GET API to get sponsor types used in a Event\n\n![sponsor_type_old](https://cloud.githubusercontent.com/assets/4047597/16110108/be118070-33c9-11e6-8532-ce104c5a57d3.png)\n\n", "before_files": [{"content": "from flask.ext.restplus import Resource, Namespace\n\nfrom open_event.models.sponsor import Sponsor as SponsorModel\n\nfrom .helpers.helpers import get_paginated_list, requires_auth, get_object_in_event\nfrom .helpers.utils import PAGINATED_MODEL, PaginatedResourceBase, ServiceDAO, \\\n    PAGE_PARAMS, POST_RESPONSES, PUT_RESPONSES\nfrom .helpers import custom_fields as fields\n\napi = Namespace('sponsors', description='Sponsors', path='/')\n\nSPONSOR = api.model('Sponsor', {\n    'id': fields.Integer(required=True),\n    'name': fields.String(),\n    'url': fields.Uri(),\n    'logo': fields.ImageUri(),\n    'description': fields.String(),\n    'level': fields.String(),\n    'sponsor_type': fields.String(),\n})\n\nSPONSOR_PAGINATED = api.clone('SponsorPaginated', PAGINATED_MODEL, {\n    'results': fields.List(fields.Nested(SPONSOR))\n})\n\nSPONSOR_POST = api.clone('SponsorPost', SPONSOR)\ndel SPONSOR_POST['id']\n\n\n# Create DAO\nclass SponsorDAO(ServiceDAO):\n    def list_types(self, event_id):\n        sponsors = self.list(event_id)\n        return list(set(\n            sponsor.sponsor_type for sponsor in sponsors\n            if sponsor.sponsor_type))\n\n\nDAO = SponsorDAO(SponsorModel, SPONSOR_POST)\n\n\n@api.route('/events/<int:event_id>/sponsors/<int:sponsor_id>')\n@api.response(404, 'Sponsor not found')\n@api.response(400, 'Sponsor does not belong to event')\nclass Sponsor(Resource):\n    @api.doc('get_sponsor')\n    @api.marshal_with(SPONSOR)\n    def get(self, event_id, sponsor_id):\n        \"\"\"Fetch a sponsor given its id\"\"\"\n        return DAO.get(event_id, sponsor_id)\n\n    @requires_auth\n    @api.doc('delete_sponsor')\n    @api.marshal_with(SPONSOR)\n    def delete(self, event_id, sponsor_id):\n        \"\"\"Delete a sponsor given its id\"\"\"\n        return DAO.delete(event_id, sponsor_id)\n\n    @requires_auth\n    @api.doc('update_sponsor', responses=PUT_RESPONSES)\n    @api.marshal_with(SPONSOR)\n    @api.expect(SPONSOR_POST)\n    def put(self, event_id, sponsor_id):\n        \"\"\"Update a sponsor given its id\"\"\"\n        return DAO.update(event_id, sponsor_id, self.api.payload)\n\n\n@api.route('/events/<int:event_id>/sponsors')\nclass SponsorList(Resource):\n    @api.doc('list_sponsors')\n    @api.marshal_list_with(SPONSOR)\n    def get(self, event_id):\n        \"\"\"List all sponsors\"\"\"\n        return DAO.list(event_id)\n\n    @requires_auth\n    @api.doc('create_sponsor', responses=POST_RESPONSES)\n    @api.marshal_with(SPONSOR)\n    @api.expect(SPONSOR_POST)\n    def post(self, event_id):\n        \"\"\"Create a sponsor\"\"\"\n        return DAO.create(\n            event_id,\n            self.api.payload,\n            self.api.url_for(self, event_id=event_id)\n        )\n\n\n@api.route('/events/<int:event_id>/sponsors/types')\nclass SponsorTypesList(Resource):\n    @api.doc('list_sponsor_types')\n    def get(self, event_id):\n        \"\"\"List all sponsor types\"\"\"\n        return DAO.list_types(event_id)\n\n\n@api.route('/events/<int:event_id>/sponsors/page')\nclass SponsorListPaginated(Resource, PaginatedResourceBase):\n    @api.doc('list_sponsors_paginated', params=PAGE_PARAMS)\n    @api.marshal_with(SPONSOR_PAGINATED)\n    def get(self, event_id):\n        \"\"\"List sponsors in a paginated manner\"\"\"\n        return get_paginated_list(\n            SponsorModel,\n            self.api.url_for(self, event_id=event_id),\n            args=self.parser.parse_args(),\n            event_id=event_id\n        )\n", "path": "open_event/api/sponsors.py"}], "after_files": [{"content": "from flask.ext.restplus import Resource, Namespace\n\nfrom open_event.models.sponsor import Sponsor as SponsorModel\n\nfrom .helpers.helpers import get_paginated_list, requires_auth, get_object_in_event\nfrom .helpers.utils import PAGINATED_MODEL, PaginatedResourceBase, ServiceDAO, \\\n    PAGE_PARAMS, POST_RESPONSES, PUT_RESPONSES\nfrom .helpers import custom_fields as fields\n\napi = Namespace('sponsors', description='Sponsors', path='/')\n\nSPONSOR = api.model('Sponsor', {\n    'id': fields.Integer(required=True),\n    'name': fields.String(),\n    'url': fields.Uri(),\n    'logo': fields.ImageUri(),\n    'description': fields.String(),\n    'level': fields.String(),\n    'sponsor_type': fields.String(),\n})\n\nSPONSOR_PAGINATED = api.clone('SponsorPaginated', PAGINATED_MODEL, {\n    'results': fields.List(fields.Nested(SPONSOR))\n})\n\nSPONSOR_POST = api.clone('SponsorPost', SPONSOR)\ndel SPONSOR_POST['id']\n\n\n# Create DAO\nclass SponsorDAO(ServiceDAO):\n    def list_types(self, event_id):\n        sponsors = self.list(event_id)\n        return list(set(\n            sponsor.sponsor_type for sponsor in sponsors\n            if sponsor.sponsor_type))\n\n\nDAO = SponsorDAO(SponsorModel, SPONSOR_POST)\n\n\n@api.route('/events/<int:event_id>/sponsors/<int:sponsor_id>')\n@api.response(404, 'Sponsor not found')\n@api.response(400, 'Sponsor does not belong to event')\nclass Sponsor(Resource):\n    @api.doc('get_sponsor')\n    @api.marshal_with(SPONSOR)\n    def get(self, event_id, sponsor_id):\n        \"\"\"Fetch a sponsor given its id\"\"\"\n        return DAO.get(event_id, sponsor_id)\n\n    @requires_auth\n    @api.doc('delete_sponsor')\n    @api.marshal_with(SPONSOR)\n    def delete(self, event_id, sponsor_id):\n        \"\"\"Delete a sponsor given its id\"\"\"\n        return DAO.delete(event_id, sponsor_id)\n\n    @requires_auth\n    @api.doc('update_sponsor', responses=PUT_RESPONSES)\n    @api.marshal_with(SPONSOR)\n    @api.expect(SPONSOR_POST)\n    def put(self, event_id, sponsor_id):\n        \"\"\"Update a sponsor given its id\"\"\"\n        return DAO.update(event_id, sponsor_id, self.api.payload)\n\n\n@api.route('/events/<int:event_id>/sponsors')\nclass SponsorList(Resource):\n    @api.doc('list_sponsors')\n    @api.marshal_list_with(SPONSOR)\n    def get(self, event_id):\n        \"\"\"List all sponsors\"\"\"\n        return DAO.list(event_id)\n\n    @requires_auth\n    @api.doc('create_sponsor', responses=POST_RESPONSES)\n    @api.marshal_with(SPONSOR)\n    @api.expect(SPONSOR_POST)\n    def post(self, event_id):\n        \"\"\"Create a sponsor\"\"\"\n        return DAO.create(\n            event_id,\n            self.api.payload,\n            self.api.url_for(self, event_id=event_id)\n        )\n\n\n@api.route('/events/<int:event_id>/sponsors/types')\nclass SponsorTypesList(Resource):\n    @api.doc('list_sponsor_types', model=[fields.String()])\n    def get(self, event_id):\n        \"\"\"List all sponsor types\"\"\"\n        return DAO.list_types(event_id)\n\n\n@api.route('/events/<int:event_id>/sponsors/page')\nclass SponsorListPaginated(Resource, PaginatedResourceBase):\n    @api.doc('list_sponsors_paginated', params=PAGE_PARAMS)\n    @api.marshal_with(SPONSOR_PAGINATED)\n    def get(self, event_id):\n        \"\"\"List sponsors in a paginated manner\"\"\"\n        return get_paginated_list(\n            SponsorModel,\n            self.api.url_for(self, event_id=event_id),\n            args=self.parser.parse_args(),\n            event_id=event_id\n        )\n", "path": "open_event/api/sponsors.py"}]}