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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_namespace_by_keyword_version(self, keyword: str, version: str) -> Optional[Namespace]: """Get a namespace with a given keyword and version."""

        filt = and_(Namespace.keyword == keyword, Namespace.version == version)
        return self.session.query(Namespace).filter(filt).one_or_none()