Sometimes, we want to declare custom exceptions in Python.

In this article, we’ll look at how to declare custom exceptions in Python.

How to declare custom exceptions in Python?

To declare custom exceptions in Python, we can create a subclass of the Exception class.

For instance, we write

class ValidationError(Exception):
    def __init__(self, message, errors):                    
        super().__init__(message)
        self.errors = errors

to create the ValidationError exception class that’s a subclass of Exception.

In the __init__ method, we call the Exception constructor with

super().__init__(message)

Then we add custom code after that like

self.errors = errors

Conclusion

To declare custom exceptions in Python, we can create a subclass of the Exception class.