class_docstr: GSSPlugin replay plugin.
  
  Code adapted from the repository:
  https://github.com/RaptorMai/online-continual-learning
  Handles an external memory fulled with samples selected
  using the Greedy approach of GSS algorithm.
  `before_forward` callback is used to process the current
  sample and estimate a score.
code: def before_training(self, strategy: "SupervisedTemplate", **kwargs):
      self.device = strategy.device
      self.ext_mem_list_x = self.ext_mem_list_x.to(strategy.device)
      self.ext_mem_list_y = self.ext_mem_list_y.to(strategy.device)
      self.buffer_score = self.buffer_score.to(strategy.device)
  
file_path: avalanche/avalanche/training/plugins/gss_greedy.py
imports: from typing import TYPE_CHECKING
  import torch
  from avalanche.benchmarks.utils import _make_taskaware_classification_dataset
  from avalanche.benchmarks.utils.data_loader import ReplayDataLoader
  from avalanche.training.plugins.strategy_plugin import SupervisedPlugin
label_desc: Use image node_id 2 for calling the GSS_greedyPlugin obj's underlying member method code with example usage: obj.before_training(strategy) without return types