Fix AuthAPI authenticaiton issue in Tornado - Fullstack python developer (vue.js frontend)

Async App Tornado based application is not starting due to authentication issue.
We are not able to debug the problem. We need experineced developer who can fix the bug so the application start.

Traceback (most recent call last):
File "/async_app.py", line 73, in <module>
app = App()
File "/async_app.py", line 23, in __init__
self.users = {user['id']: user for user in AuthAPI.get_users()}
File "/async_app.py", line 23, in <dictcomp>
self.users = {user['id']: user for user in AuthAPI.get_users()}
TypeError: string indices must be integers

The freelancer who will be able to fix this issue will continue on the project.