code: 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'],
          f _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'],
          )
docs: Build FTP client.