class_docstr: DummyListMetric for testing core components.
code: def __init__(self, **kwargs: Any) -> None:
      super().__init__(**kwargs)
      self.add_state("x", [], dist_reduce_fx="cat")
  
imports: import pickle
  import sys
  from copy import deepcopy
  from functools import partial
  from typing import Any, Callable, Dict, List, Optional, Sequence, Tuple, Union
  import numpy
  import pytest
  import torch
  from lightning_utilities import apply_to_collection
  from torch import Tensor, tensor
  from torchmetrics import Metric
  from torchmetrics.utilities.data import _flatten
  from unittests import NUM_PROCESSES
label_desc: Use image node_id 1 to create a new DummyListMetric object from inherited base classes: Metric with example: obj = DummyListMetric()