AttributeError: 'Blueprint' object has no attribute 'json_encoder'

[apachipa]

When i try createdb i get this below error:
Just wondering if anyone came across this before.
I am trying install OK server on Ubuntu 16.04:

./manage.py createdb

Traceback (most recent call last):
File "./manage.py", line 124, in
manager.run()
File "/home/username/ok/env/lib/python3.5/site-packages/flask_script/init.py", line 412, in run
result = self.handle(sys.argv[0], sys.argv[1:])
File "/home/username/ok/env/lib/python3.5/site-packages/flask_script/init.py", line 383, in handle
res = handle(*args, **config)
File "/home/username/ok/env/lib/python3.5/site-packages/flask_script/commands.py", line 215, in call
with app.test_request_context():
File "/home/username/ok/env/lib/python3.5/site-packages/flask/ctx.py", line 390, in enter
self.push()
File "/home/username/ok/env/lib/python3.5/site-packages/flask/ctx.py", line 332, in push
self.session = self.app.open_session(self.request)
File "/home/username/ok/env/lib/python3.5/site-packages/flask/app.py", line 912, in open_session
return self.session_interface.open_session(self, request)
File "/home/username/ok/env/lib/python3.5/site-packages/flask/sessions.py", line 324, in open_session
s = self.get_signing_serializer(app)
File "/home/username/ok/env/lib/python3.5/site-packages/flask/sessions.py", line 321, in get_signing_serializer
signer_kwargs=signer_kwargs)
File "/home/username/ok/env/lib/python3.5/site-packages/itsdangerous.py", line 519, in init
self.is_text_serializer = is_text_serializer(serializer)
File "/home/username/ok/env/lib/python3.5/site-packages/itsdangerous.py", line 69, in is_text_serializer
return isinstance(serializer.dumps({}), text_type)
File "/home/username/ok/env/lib/python3.5/site-packages/flask/sessions.py", line 85, in dumps
return json.dumps(_tag(value), separators=(',', ':'))
File "/home/username/ok/env/lib/python3.5/site-packages/flask/json/init.py", line 177, in dumps
_dump_arg_defaults(kwargs)
File "/home/username/ok/env/lib/python3.5/site-packages/flask/json/init.py", line 98, in _dump_arg_defaults
bp.json_encoder if bp and bp.json_encoder
AttributeError: 'Blueprint' object has no attribute 'json_encoder'

Any help will be much appreciated. Thanks In advance.

Regards,
Ash

[colinschoen]

Hi Ash,

I received another report of this issue. I will investigate shortly.