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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def errorhandler(self, code_or_exception):
 """ Registers an error handler that becomes active for this bundle only. Please be aware that routing does not happen local to a bundle so an error handler for 404 usually is not handled by a bundle unless it is caused inside a view function. Another special case is the 500 internal server error which is always looked up from the application. Otherwise works as the :meth:`flask.Blueprint.errorhandler` decorator. """

        def decorator(fn):
            self._defer(lambda bp: bp.register_error_handler(code_or_exception, fn))
            return fn
        return decorator