code: def test_get_top_k_items(rating_true):
      top_3_items_df = get_top_k_items(
          dataframe=rating_true,
          col_user=DEFAULT_USER_COL,
          col_rating=DEFAULT_RATING_COL,
          k=3,
      )
      top_3_user_true = pd.Series([1, 1, 1, 2, 2, 2, 3, 3, 3])
      top_3_rating_true = pd.Series([5, 4, 3, 5, 5, 3, 5, 5, 5])
      top_3_rank_true = pd.Series([1, 2, 3, 1, 2, 3, 1, 2, 3])
      assert top_3_items_df[DEFAULT_USER_COL].equals(top_3_user_true)
      assert top_3_items_df[DEFAULT_RATING_COL].equals(
          top_3_rating_true
      )
      assert top_3_items_df["rank"].equals(top_3_rank_true)
      assert top_3_items_df[DEFAULT_ITEM_COL][:3].equals(
          pd.Series([1, 2, 3])
      )
      # First two itemIDs of user 2. The scores are both 5, so any order is OK.
      assert set(top_3_items_df[DEFAULT_ITEM_COL][3:5]) == set([1, 4])
      # Third itemID of user 2. Both item 5 and 6 have a score of 3, so either one is OK.
      assert top_3_items_df[DEFAULT_ITEM_COL][5] in [5, 6]
      # All itemIDs of user 3. All three items have a score of 5, so any order is OK.
      assert set(top_3_items_df[DEFAULT_ITEM_COL][6:]) == set([2, 5, 6])
  
imports: import numpy
  import pandas
  import pytest
  from unittest.mock import Mock
  from sklearn.preprocessing import minmax_scale
  from pandas.testing import assert_frame_equal
  from recommenders.utils.constants import DEFAULT_USER_COL, DEFAULT_ITEM_COL, DEFAULT_RATING_COL, DEFAULT_PREDICTION_COL
  from recommenders.evaluation.python_evaluation import _check_column_dtypes, merge_rating_true_pred, merge_ranking_true_pred, rmse, mae, rsquared, exp_var, get_top_k_items, precision_at_k, recall_at_k, ndcg_at_k, map_at_k, map, auc, logloss, user_diversity, diversity, historical_item_novelty, novelty, user_item_serendipity, user_serendipity, serendipity, catalog_coverage, distributional_coverage, ColumnMismatchError, ColumnTypeMismatchError
label_desc: Use image node_id 10 for calling a global function with example usage: test_get_top_k_items(rating_true) without return types