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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_ftp_client(cls, session: AppSession):
        '''Build FTP client.'''
        return session.factory.new(
            'FTPClient',
            connection_pool=session.factory['ConnectionPool'],
            # TODO: recorder
            # recorder=session.factory['DemuxRecorder'],
        )