class_docstr: Linear adapter for Progressive Neural Networks.
code: def forward(self, x):
      assert len(x) == self.num_prev_modules
      hs = []
      for ii, lat in enumerate(self.lat_layers):
          hs.append(lat(x[ii]))
      return sum(hs)
  
imports: import torch
  import torch.nn.functional
  from torch import nn
  from avalanche.benchmarks.utils.flat_data import ConstantSequence
  from avalanche.models import MultiTaskModule
  from avalanche.models import MultiHeadClassifier
  from avalanche.benchmarks.scenarios import CLExperience
label_desc: Use image node_id 2 for calling the LinearAdapter obj's underlying member method code with example usage: obj.forward(x) and returns: sum