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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 default_update_stack(self, fqn, template, old_parameters, parameters, tags, stack_policy=None, **kwargs):
 """Update a Cloudformation stack in default mode. Args: fqn (str):
 The fully qualified name of the Cloudformation stack. template (:class:`stacker.providers.base.Template`):
 A Template object to use when updating the stack. old_parameters (list):
 A list of dictionaries that defines the parameter list on the existing Cloudformation stack. parameters (list):
 A list of dictionaries that defines the parameter list to be applied to the Cloudformation stack. tags (list):
 A list of dictionaries that defines the tags that should be applied to the Cloudformation stack. stack_policy (:class:`stacker.providers.base.Template`):
 A template object representing a stack policy. """


        logger.debug("Using default provider mode for %s.", fqn)
        args = generate_cloudformation_args(
            fqn, parameters, tags, template,
            service_role=self.service_role,
            stack_policy=stack_policy,
        )

        try:
            self.cloudformation.update_stack(**args)
        except botocore.exceptions.ClientError as e:
            if "No updates are to be performed." in str(e):
                logger.debug(
                    "Stack %s did not change, not updating.",
                    fqn,
                )
                raise exceptions.StackDidNotChange
            elif e.response['Error']['Message'] == ('TemplateURL must '
                                                    'reference a valid '
                                                    'S3 object to which '
                                                    'you have access.'):
                s3_fallback(fqn, template, parameters, tags,
                            self.cloudformation.update_stack,
                            self.service_role)
            else:
                raise