class_docstr: Mixin to test a bunch of common functionality in models
  deriving from RecommenderBase
code: def test_rank_items_batch(self):
      item_users = get_checker_board(50)
      user_items = item_users.T.tocsr()
  
      model = self._get_model()
      model.fit(item_users, show_progress=False)
  
      selected_items = np.arange(10) * 3
      try:
          ids, _ = model.recommend(
              np.arange(50), user_items, items=selected_items
          )
      except NotImplementedError:
          return
  
      for userid in range(50):
          current_ids = ids[userid]
          self.assertEqual(set(current_ids), set(selected_items))
  
imports: import os
  import pickle
  import random
  import tempfile
  import numpy
  import pytest
  from numpy.testing import assert_array_equal
  from scipy.sparse import coo_matrix, csr_matrix
  from implicit.evaluation import precision_at_k
  from implicit.nearest_neighbours import ItemItemRecommender
  from implicit.utils import ParameterWarning
label_desc: Use image node_id 17 for calling the RecommenderBaseTestMixin obj's underlying member method code with example usage: obj.test_rank_items_batch() without return types