code: def test_n_tasks_param(self):
      for stream in self.stream_lengths.keys():
          with self.subTest(stream=stream):
              with self.assertRaises(ValueError):
                  CTrL(stream, n_tasks=3)
  
      with self.subTest(stream="s_long"):
          CTrL("s_long", n_tasks=3)
  
file_path: avalanche/tests/benchmarks/classic/test_ctrl.py
imports: import unittest
  from pathlib import Path
  from tempfile import TemporaryDirectory
  import torch
  from tests.unit_tests_utils import FAST_TEST, is_github_action
label_desc: Use image node_id 3 for calling the CTrLTests obj's underlying member method code with example usage: obj.test_n_tasks_param() without return types