How to prompt for Username and Password with SqlAlchemy

We are using SqlAlchemy to connect to Connect to Splice database. In options use this format for url

options=’{“url”: "splicemachinesa://${USER}:${PASSWORD}@…}

This is only resulting in display of the message ‘Missing username and/or password’ and there the Auth dialog does not get displayed.

In notebook.js, show auth dialog iin case of status=401 is for

And in SqlAlchemyApi, create_session does not raise AuthenticationRequired. Only create_engine raises AuthenticationRequired.

And the AuthenticationRequired raised in create_engine, results in just displaying the error message.

SO how do i get it to prompt the user for username and password when using SqlAlchemy. ALso noticed with JDBC, it does prompt the user correctly.