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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 _build_document_converter(cls, session: AppSession):
        '''Build the Document Converter.'''

        if not session.args.convert_links:
            return

        converter = session.factory.new(
            'BatchDocumentConverter',
            session.factory['HTMLParser'],
            session.factory['ElementWalker'],
            session.factory['URLTable'],
            backup=session.args.backup_converted
        )

        return converter