本地版本上的 Django social_auth facebook 后端运行良好，但该站点的生产版本响应以下错误：
Traceback (most recent call last):
File "/home/my_user/my_project/venv/lib/python2.7/site-packages/django/core/handlers/base.py", line 201, in get_response
response = middleware_method(request, response)
File "/home/my_user/my_project/venv/lib/python2.7/site-packages/django/contrib/sessions/middleware.py", line 38, in process_response
request.session.save()
File "/home/my_user/my_project/venv/lib/python2.7/site-packages/django/contrib/sessions/backends/cached_db.py", line 62, in save
super(SessionStore, self).save(must_create)
File "/home/my_user/my_project/venv/lib/python2.7/site-packages/django/contrib/sessions/backends/db.py", line 57, in save
session_data=self.encode(self._get_session(no_load=must_create)),
File "/home/my_user/my_project/venv/lib/python2.7/site-packages/django/contrib/sessions/backends/base.py", line 87, in encode
serialized = self.serializer().dumps(session_dict)
File "/home/my_user/my_project/venv/lib/python2.7/site-packages/django/core/signing.py", line 88, in dumps
return json.dumps(obj, separators=(',', ':')).encode('latin-1')
File "/usr/lib/python2.7/json/__init__.py", line 238, in dumps
**kw).encode(obj)
File "/usr/lib/python2.7/json/encoder.py", line 201, in encode
chunks = self.iterencode(o, _one_shot=True)
File "/usr/lib/python2.7/json/encoder.py", line 264, in iterencode
return _iterencode(o, 0)
File "/usr/lib/python2.7/json/encoder.py", line 178, in default
raise TypeError(repr(o) + " is not JSON serializable")
TypeError: <social_auth.backends.facebook.FacebookBackend object at 0x7fd0543fe710> is not JSON serializable
唯一的区别是本地版本使用 django1.5 而生产使用 django1.6 这可能是一个原因，我该怎么办？Django_social_auth 0.7.27