code: def test_default_namespace(self) -> None:
      helper = NamespaceHelper.from_namespaced_entity("add")
      self.assertEqual(helper.entity_name, "add")
      self.assertEqual(helper.get_cpp_namespace(), "")
      self.assertEqual(helper.get_cpp_namespace("default"), "default")
  
imports: import unittest
  from torchgen.utils import NamespaceHelper
label_desc: Use image node_id 2 for calling the TestNamespaceHelper obj's underlying member method code with example usage: obj.test_default_namespace() without return types