code: def _maybe_merge_subsets(d1: FlatData, d2: FlatData):
      """Check the conditions for merging subsets."""
      if (not d1._can_flatten) or (not d2._can_flatten):
          return [d1, d2]
  
      if (
          len(d1._datasets) == 1
          and len(d2._datasets) == 1
          and d1._datasets[0] is d2._datasets[0]
      ):
          # return [d1.__class__(d1._datasets, d1._indices + d2._indices)]
          return [d1.concat(d2)]
      return [d1, d2]
  
imports: import bisect
  import sys
  import numpy
  from avalanche.benchmarks.utils.dataset_utils import slice_alike_object_to_indices
  from typing import Iterable, List, Optional, Sequence, Tuple, TypeVar, Union, overload
  from torch.utils.data import ConcatDataset
  import itertools
  from avalanche.benchmarks.utils.dataset_definitions import IDataset
label_desc: Use image node_id 3 for calling a global function with example usage: _maybe_merge_subsets(d1, d2) and returns: list, list, list