code: def dim_zero_cat(x: Union[Tensor, List[Tensor]]) -> Tensor:
      """Concatenation along the zero dimension."""
      if isinstance(x, torch.Tensor):
          return x
      x = [
          y.unsqueeze(0) if y.numel() == 1 and y.ndim == 0 else y
          for y in x
      ]
      if not x:  # empty list
          raise ValueError("No samples to concatenate")
      return torch.cat(x, dim=0)
  
imports: import sys
  from typing import Any, Dict, List, Optional, Sequence, Tuple, Union
  import torch
  from lightning_utilities import apply_to_collection
  from torch import Tensor
  from torchmetrics.utilities.exceptions import TorchMetricsUserWarning
  from torchmetrics.utilities.imports import _TORCH_GREATER_EQUAL_1_12, _TORCH_GREATER_EQUAL_1_13, _XLA_AVAILABLE
  from torchmetrics.utilities.prints import rank_zero_warn
label_desc: Use image node_id 1 for calling a global function with example usage: dim_zero_cat(x) and returns: torch, x