code: def setUp(self) -> None:
      self.initial_callback = MagicMock(spec=Callback)
      self.callback_list = CallbackList([self.initial_callback])
  
imports: from unittest import TestCase
  from unittest.mock import MagicMock
  from poutyne import Callback, CallbackList
label_desc: Use image node_id 1 for calling the CallbackListTest obj's underlying member method code with example usage: obj.setUp() without return types