code: def detection_collate_mbatches_fn(
      mbatches: Sequence[DetectionBatchT],
  ) -> DetectionBatchT:
      """
      Collate function used when loading detection datasets using a DataLoader.
  
      This will merge multiple batches to create a concatenated batch.
  
      Beware that merging multiple batches is different from creating a batch
      from single dataset elements: Batches can be created from a
      list of single dataset elements by using :func:`detection_collate_fn`.
      """
  
      # The code used here is equivalent to the following one:
      # images: List[Tuple[Tensor, ...]] = []
      # targets: List[Tuple[Dict, ...]] = []
      # task_labels: List[Tuple[int, ...]] = []
  
      # for mb in mbatches:
      #     images.append(mb[0])
      #     targets.append(mb[1])
      #     task_labels.append(mb[2])
  
      # batched_images = tuple(itertools.chain.from_iterable(images))
      # batched_targets = tuple(itertools.chain.from_iterable(targets))
      # batched_task_labels = tuple(itertools.chain.from_iterable(task_labels))
  
      # return batched_images, batched_targets, batched_task_labels
  
      lists_dict: Dict[int, List] = defaultdict(list)
      for mb in mbatches:
          for mb_elem_idx, mb_elem in enumerate(mb):
              lists_dict[mb_elem_idx].append(mb_elem)
  
      batch_elements = []
      for mb_elem_idx in range(max(lists_dict.keys()) + 1):
          batch_elements.append(
              tuple(
                  itertools.chain.from_iterable(lists_dict[mb_elem_idx])
              )
          )
  
      return tuple(batch_elements)
  
file_path: avalanche/avalanche/benchmarks/utils/collate_functions.py
imports: import itertools
  from abc import ABC, abstractmethod
  from collections import defaultdict
  from typing import List, TypeVar, Generic, Sequence, Tuple, Dict, Union, overload
  from typing_extensions import TypeAlias
  import torch
  from torch import Tensor
  from torch.utils.data import default_collate
label_desc: Use image node_id 5 for calling a global function with example usage: detection_collate_mbatches_fn(mbatches) and returns: tuple