docstr: Expand the data tensor along one dimension.
  The shape cannot shrink. It cannot add new dimensions, either.
  If the shape does not change, this method does nothing.
  
  :param new_shape: expanded shape
  :param padding_fn: function used to create the padding
      around the expanded tensor.
  
  :return the expanded tensor or the previous tensor
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code: def expand(self, new_shape, padding_fn=torch.zeros):
      """
      Expand the data tensor along one dimension.
      The shape cannot shrink. It cannot add new dimensions, either.
      If the shape does not change, this method does nothing.
  
      :param new_shape: expanded shape
      :param padding_fn: function used to create the padding
          around the expanded tensor.
  
      :return the expanded tensor or the previous tensor
      """
      assert len(new_shape) == len(
          self.shape
      ), "Expansion cannot add new dimensions"
      expanded = False
      for i, (snew, sold) in enumerate(zip(new_shape, self.shape)):
          assert snew >= sold, "Shape cannot decrease."
          if snew > sold:
              assert (
                  not expanded
              ), "Expansion cannot occur in more than one dimension."
              expanded = True
              exp_idx = i
  
      if expanded:
          old_data = self._data.clone()
          old_shape_len = self._data.shape[exp_idx]
          self.reset_like(new_shape, init_function=padding_fn)
          idx = [
              slice(el) if i != exp_idx else slice(old_shape_len)
              for i, el in enumerate(new_shape)
          ]
          self._data[idx] = old_data
      return self.data
  
imports: from collections import defaultdict
  from typing import Callable, Dict, List, NamedTuple, Optional, Tuple, Union
  import torch
  from torch import Tensor
  from torch.nn import Linear, Module
  from torch.utils.data import DataLoader, Dataset
  from avalanche.benchmarks import OnlineCLExperience
  from avalanche.models.batch_renorm import BatchRenorm2D
label_desc: Use image node_id 3 for calling the ParamData obj's underlying member method code with example usage: obj.expand(new_shape, padding_fn) and returns: self