class_docstr: Progressive Neural Network column.
code: def freeze(self):
      for param in self.parameters():
          param.requires_grad = False
  
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 PNNColumn obj's underlying member method code with example usage: obj.freeze() without return types