code: def test_from_splits(self):
      next_item_eval = NextItemEvaluation.from_splits(
          train_data=self.data[:50],
          test_data=self.data[50:],
          fmt="USIT",
      )
  
      self.assertTrue(next_item_eval.train_set != None)
      self.assertTrue(next_item_eval.test_set != None)
      self.assertTrue(next_item_eval.val_set == None)
      self.assertTrue(next_item_eval.total_sessions == 16)
  
file_path: cornac/tests/cornac/eval_methods/test_next_item_evaluation.py
imports: import unittest
  from cornac.eval_methods import NextItemEvaluation
  from cornac.data import Reader
  from cornac.models import SPop
  from cornac.metrics import HitRatio, Recall
label_desc: Use image node_id 2 for calling the TestNextItemEvaluation obj's underlying member method code with example usage: obj.test_from_splits() without return types