class_docstr: Mixin to test a bunch of common functionality in models
  deriving from RecommenderBase
code: def test_invalid_user_items(self):
      user_items = get_checker_board(50)
      model = self._get_model()
      model.fit(user_items, show_progress=False)
  
      with self.assertRaises(ValueError):
          model.recommend(0, user_items=user_items.tocsc())
  
      with self.assertRaises(ValueError):
          model.recommend(0, user_items=user_items.tocoo())
  
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 20 for calling the RecommenderBaseTestMixin obj's underlying member method code with example usage: obj.test_invalid_user_items() without return types