Tornado OAuth2 Error in get_argument() (Facebook change) - python-3.x

Question

I have a problem that I can't work out. My code worked for localhost however how I have a proper domain setup i'm getting some strange problems trying to login with facebook. I have since moved to python 3.6
I have the following tornado setup code:
handlers = [
(r"/facebookAuth",FBAuth),
# other handlers...
]
# Settings dict for Application
settings = {
# static handler
# Set specific HTTP404 errors to Error404 Class
"default_handler_class": Error404,
"cookie_secret":"xxx",
"facebook_redirect_uri":"https://www.example.com/facebookAuth",
"facebook_secret":"xxx",
"facebook_app_id":"xxx",
}
class FBAuth(BaseHandler,tornado.auth.FacebookGraphMixin):
async def get(self):
if self.get_argument("code", False):
print("not code")
user = await self.get_authenticated_user(redirect_uri=self.settings["facebook_redirect_uri"],
client_id=self.settings["facebook_app_id"],
client_secret=self.settings["facebook_secret"],
code=self.get_argument("code"))
print("******")
print(user)
firstName=user["first_name"]
lastName=user["last_name"]
# set cookie and start up code
else:
print("code")
await self.authorize_redirect(redirect_uri=self.settings["facebook_redirect_uri"],
client_id=self.settings["facebook_app_id"],
scope=["email","public_profile"])
I can't work out the result of the code. It shows:
code
not code
and crashes with the following:
Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/tornado-4.5.dev1-py3.6-linux-x86_64.egg/tornado/web.py", line 1474, in _execute
result = yield result
File "/usr/local/lib/python3.6/site-packages/tornado-4.5.dev1-py3.6-linux-x86_64.egg/tornado/gen.py", line 1045, in run
value = future.result()
File "/usr/local/lib/python3.6/site-packages/tornado-4.5.dev1-py3.6-linux-x86_64.egg/tornado/concurrent.py", line 237, in result
raise_exc_info(self._exc_info)
File "<string>", line 3, in raise_exc_info
File "/usr/local/lib/python3.6/site-packages/tornado-4.5.dev1-py3.6-linux-x86_64.egg/tornado/gen.py", line 1051, in run
yielded = self.gen.throw(*exc_info)
File "<string>", line 6, in _wrap_awaitable
File "/home/cs/charliesays/authHandlers.py", line 13, in get
code=self.get_argument("code"))
File "<string>", line 3, in __await__
File "/usr/local/lib/python3.6/site-packages/tornado-4.5.dev1-py3.6-linux-x86_64.egg/tornado/gen.py", line 1045, in run
value = future.result()
File "/usr/local/lib/python3.6/site-packages/tornado-4.5.dev1-py3.6-linux-x86_64.egg/tornado/concurrent.py", line 237, in result
raise_exc_info(self._exc_info)
File "<string>", line 3, in raise_exc_info
File "/usr/local/lib/python3.6/site-packages/tornado-4.5.dev1-py3.6-linux-x86_64.egg/tornado/stack_context.py", line 314, in wrapped
ret = fn(*args, **kwargs)
File "/usr/local/lib/python3.6/site-packages/tornado-4.5.dev1-py3.6-linux-x86_64.egg/tornado/auth.py", line 983, in _on_access_token
"access_token": args["access_token"][-1],
KeyError: 'access_token'
It seems there is a problem with the:
code=self.get_argument("code") in the call to get_authenticated_user()