code: def test_densify_sampled_item_predictions(self):
      input_data = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12])
      result = densify_sampled_item_predictions(
          tf_sample_predictions_serial=input_data,
          tf_n_sampled_items=4,
          tf_n_users=3,
      ).eval(session=self.session)
  
      expected_result = np.array(
          [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
      )
      self.assertTrue((result == expected_result).all())
  
file_path: tensorrec/test/test_recommendation_graphs.py
imports: import numpy
  import tensorflow
  import scipy.sparse
  from unittest import TestCase
  from tensorrec.prediction_graphs import CosineSimilarityPredictionGraph
  from tensorrec.recommendation_graphs import project_biases, split_sparse_tensor_indices, bias_prediction_dense, bias_prediction_serial, densify_sampled_item_predictions, rank_predictions, collapse_mixture_of_tastes, predict_similar_items
  from tensorrec.session_management import get_session
label_desc: Use image node_id 6 for calling the RecommendationGraphsTestCase obj's underlying member method code with example usage: obj.test_densify_sampled_item_predictions() without return types