Python MaybeMonad

main.py

from __future__ import annotations
from asyncio.log import logger
from typing import Callable


class MaybeMonad():
    def __init__(
        self,
        value: object
    ) -> None:
        self.value = value


    def bind(
        self,
        func: Callable,
        *args
    ) -> MaybeMonad:
        if not self.is_valid():
            return MaybeMonad(None)

        try:
            self.value = func(self.value, *args)
            return self
        except Exception as e:
            logger.warning(f"Binding '{func.__name__}' raised exception '{e}'. Your monad is now invalid.")
            return MaybeMonad(None)


    def is_valid(self):
        return (self.value != None)


    def __str__(self):
        return str(self.value)


# Some functions you need to chain.
def get_user(id: int):
    return "Geoff"


def add_title(name: str, title: str):
    return f"{title}. {name}"


def add_suffix(name: str, suffix: str):
    raise Exception("EVIL NULL!")       # Raise exception to illustrate. Uncomment for success.
    # return f"{name} {suffix}."        # Uncomment for success


def greet(name: str):
    return f"Hello {name}"


# Main
def main():
    greeting = MaybeMonad(get_user(id=1)) \
        .bind(add_title, "Dr") \
        .bind(add_suffix, "jr") \
        .bind(greet)

    print(str(greeting))


if __name__ == '__main__':
    main()

Using *args is pretty nice as it allows binding functions with n params.