How to get the usernames and hashed passwords of my MongoDB atlas database users (especially using python)

For my flask application, I am trying to implement login and page access with flask-login. However, the examples of flask-login used online are all done using SQL and SQLAlchemy. I am going to use MongoDB Atlas to store my users (i.e once I create a mongo atlas database user, they will be able to log into my application using their atlas dB username and password). For the login function, I will need to compare the username and password of the person trying to log into my application with the username and password of the Mongo Atlas Db user. How can I get the usernames and passwords of the Mongo Atlas users with python?