I'm using Python 3.6.5.
Class A, below for me represents a database table, using SQLAlchemy.
I'm defining a @staticmethod method that returns a row, but if there's no result, it would return None.
Since it returns an instance of class A, then the notation normally goes:
-> A: 
at the end of the def signature, but because A is not yet defined, as it's on class A itself, you are supposed to quote it as:
-> 'A':
Is the -> 'A': sufficient?
Or is there some sort of OR syntax?
Thanks in advance for your advice.
You can use Optional[A], this means that it can return A or None
To make a "or" between classes A and B, use Union[A, B]
Note that you should import Optional and Union from typing
Python PEP 484 Type Hints -> return type either class name or None?