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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 dumps(self, bucket=None):
 """Serialize files from a bucket. :param bucket: Instance of files :class:`invenio_files_rest.models.Bucket`. (Default: ``self.bucket``) :returns: List of serialized files. """

        return [
            self.file_cls(o, self.filesmap.get(o.key, {})).dumps()
            for o in sorted_files_from_bucket(bucket or self.bucket, self.keys)
        ]