How to make a custom exception class with multiple init args pickleable

Question

Why does my custom Exception class below not serialize/unserialize correctly using the pickle module?

import pickle

class MyException(Exception):
    def __ini         


        

Answer 1

I simply do this

class MyCustomException(Exception):
    def __init__(self):
        self.value = 'Message about my error'

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

... somewhere in code ...
raise MyCustomException