def get_metrics(
        self, trainer: "pl.Trainer", pl_module: "pl.LightningModule"
    ) -> dict[str, Union[int, str, float, dict[str, float]]]:
        r"""Combines progress bar metrics collected from the trainer with standard metrics from get_standard_metrics.
        Implement this to override the items displayed in the progress bar.

        Here is an example of how to override the defaults:

        .. code-block:: python

            def get_metrics(self, trainer, model):
                # don't show the version number
                items = super().get_metrics(trainer, model)
                items.pop("v_num", None)
                return items

        Return:
            Dictionary with the items to be displayed in the progress bar.

        """
        standard_metrics = get_standard_metrics(trainer)
        pbar_metrics = trainer.progress_bar_metrics
        duplicates = list(standard_metrics.keys() & pbar_metrics.keys())
        if duplicates:
            rank_zero_warn(
                f"The progress bar already tracks a metric with the name(s) '{', '.join(duplicates)}' and"
                f" `self.log('{duplicates[0]}', ..., prog_bar=True)` will overwrite this value. "
                " If this is undesired, change the name or override `get_metrics()` in the progress bar callback.",
            )

        return {**standard_metrics, **pbar_metrics}
Combines progress bar metrics collected from the trainer with standard metrics from get_standard_metrics.
        Implement this to override the items displayed in the progress bar.

        Here is an example of how to override the defaults:

        .. code-block:: python

            def get_metrics(self, trainer, model):
                # don't show the version number
                items = super().get_metrics(trainer, model)
                items.pop("v_num", None)
                return items

        Return:
            Dictionary with the items to be displayed in the progress bar.

        
src/lightning/pytorch/callbacks/progress/progress_bar.py