IO monad in Python

iomonad.py

from collections.abc import Callable
from dataclasses import dataclass

import traceback


@dataclass(frozen=True)
class IO:
    _action: Callable
    allowedExceptions: tuple = ()

    @classmethod
    def unit(cls, x):
        return cls(lambda: x)

    @classmethod
    def wrap(cls, f, allowedExceptions=()):
        return lambda *args, **kwargs: cls(
            lambda: f(*args, **kwargs),
            allowedExceptions,
        )

    def __call__(self):
        try:
            return self._action()
        except self.allowedExceptions as e:
            return e

    def bind(self, f):
        return IO(lambda: f(self())())

    def seq(self, other):
        """Equivalent to self.bind(lambda x: other)."""
        @IO
        def action():
            self()
            return other()
        return action

IO.done = IO.unit(None)


ioInput = IO(input, EOFError)
ioPrint = IO.wrap(print)

def echoLoop(s):
    return IO.done if isinstance(s, EOFError) else ioPrint(s).seq(echo)

echo = ioInput.bind(echoLoop)

echo()