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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 get(cls, bucket, key, upload_id, with_completed=False):
 """Fetch a specific multipart object."""

        q = cls.query.filter_by(
            upload_id=upload_id,
            bucket_id=as_bucket_id(bucket),
            key=key,
        )
        if not with_completed:
            q = q.filter(cls.completed.is_(False))

        return q.one_or_none()