class Auth0Error(Exception):
    def __init__(self, status_code, error_code, message):
        self.status_code = status_code
        self.error_code = error_code
        self.message = message

    def __str__(self):
        return '{}: {}'.format(self.status_code, self.message)


class TokenValidationError(Exception):
    def __init__(self, message):
        self.message = message

    def __str__(self):
        return self.message

class Auth0Error(Exception):
    def __init__(self, status_code, error_code, message):
        self.status_code = status_code
        self.error_code = error_code
        self.message = message

    def __str__(self):
        return '{}: {}'.format(self.status_code, self.message)


class TokenValidationError(Exception):
    pass

simplify the exception class definition