code: def initialize_active_learner(active_learner, y_train):
      indices_initial = random_initialization_stratified(y_train, 20)
      active_learner.initialize_data(
          indices_initial, y_train[indices_initial]
      )
  
      return indices_initial
  
file_path: small-text/examples/examplecode/pytorch_multiclass_classification.py
imports: import torch
  import numpy
  from small_text import ActiveLearnerException, EmptyPoolException, ExpectedGradientLength, KimCNNFactory, PoolBasedActiveLearner, PoolExhaustedException, random_initialization_stratified
  from examplecode.data.example_data_multiclass import get_train_test, preprocess_data
  from examplecode.shared import evaluate
label_desc: Use image node_id 4 for calling a global function with example usage: initialize_active_learner(active_learner, y_train) and returns: indices_initial