code: def test_fail_when_already_has_doc(self) -> None:
      with self.assertRaises(ValueError):
  
          @copy_doc(has_doc)
          # pyre-fixme[3]: Return type must be annotated.
          def inherits_doc():
              """I already have a doc string"""
              pass
  
file_path: Ax/ax/utils/common/tests/test_docutils.py
imports: from ax.utils.common.docutils import copy_doc
  from ax.utils.common.testutils import TestCase
label_desc: Use image node_id 2 for calling the TestDocUtils obj's underlying member method code with example usage: obj.test_fail_when_already_has_doc() without return types