How to set up relations between features and steps?

[Azat Salimgaraev]

In examples all scenarios use methods from only one *.py file - steps.py How to set up relations between *.feature and its *.py file?

I have these feature files:

auth.feature
pay.feature

and these py files

auth.py
pay.py

I need this: scenarios from the auth.feature refer to the methods only in auth.py and scenarios from the pay.feature refer only to the methods in pay.py