code: def test_rich_progress_bar_metrics_theme_update(*_):
      theme = RichProgressBar().theme
      assert theme.metrics_format == ".3f"
      assert theme.metrics_text_delimiter == " "
  
      theme = RichProgressBar(
          theme=RichProgressBarTheme(
              metrics_format=".3e", metrics_text_delimiter="\n"
          )
      ).theme
      assert theme.metrics_format == ".3e"
      assert theme.metrics_text_delimiter == "\n"
  
imports: import pickle
  from collections import defaultdict
  from unittest import mock
  from unittest.mock import DEFAULT, Mock
  import pytest
  from lightning.pytorch import Trainer
  from lightning.pytorch.callbacks import ProgressBar, RichProgressBar
  from lightning.pytorch.callbacks.progress.rich_progress import RichProgressBarTheme
  from lightning.pytorch.demos.boring_classes import BoringModel, RandomDataset, RandomIterableDataset
  from lightning.pytorch.loggers import CSVLogger
  from lightning.pytorch.loggers.logger import DummyLogger
  from tests_pytorch.helpers.runif import RunIf
  from torch.utils.data import DataLoader
label_desc: Use image node_id 22 for calling a global function with example usage: test_rich_progress_bar_metrics_theme_update() without return types