I want to implement a function that creates a CSV reader and annotate it correctly. Simplified example: import csv def create_my_csv( fh ) -> WHAT_IS_NEEDED_HERE?: return csv.reader( fh, delimiter=";", strict=True ) The problem is that csv.reader() is a function which is imported from the _csv module. This module also contains the Reader class. So maybe I could use _csv.Reader as return type - but this would make use of an implementation detail. I would rather write something like def create_my_csv( fh ) -> return_type_of( csv.reader ) Continue reading...
