benji-york

from typing import Callable, TypeVar, ParamSpec, Iterable, Any
import functools

P = ParamSpec('P')
Q = TypeVar('Q')
R = TypeVar('R')


def postprocess(post_func: Callable[[Q], R]) -> Callable[[Callable[P, Q]], Callable[P, R]]:
    """A decorator that filters a function's return value through a callable.

benji-york

# th30z@u1310:[Desktop]$ psql -h localhost -p 55432
# Password: 
# psql (9.1.10, server 0.0.0)
# WARNING: psql version 9.1, server version 0.0.
#          Some psql features might not work.
# Type "help" for help.
# 
# th30z=> select foo;
#  a | b 
# ---+---