keras/src/callbacks/progbar_logger.py/ProgbarLogger/_finalize_progbar
class ProgbarLogger:    def _finalize_progbar(self, logs):
        logs = logs or {}
        if self.target is None:
            self.target = self.seen
            self.progbar.target = self.target
        self.progbar.update(self.target, list(logs.items()), finalize=True)