how to import all classes at once?

[MichaelMrt]

After I installed the module with pip install deutsche_bahn_api I imported it with

from deutsche_bahn_api import *
api = ApiAuthentication("YOUR_CLIENT_ID", "YOUR_CLIENT_SECRET")

Now the program is not able to find the ApiAuthentication class.
Same when using:

deutsche_bahn_api.ApiAuthentication(..)

On the other hand if I import this way

import deutsche_bahn_api.api_authentication as dba
api = dba.ApiAuthentication("YOUR_CLIENT_ID", "YOUR_CLIENT_SECRET")

Everthing works fine and the class is found.

Can somebody please explain to me why the ApiAuthentication class has to be imported this way?