code: def test_copy_clean(self):
      node = parser.parse(
          textwrap.dedent(
              """
        def f(a):
          return a + 1
      """
          )
      )
      setattr(node, "__foo", "bar")
      new_node = ast_util.copy_clean(node)
      self.assertIsNot(new_node, node)
      self.assertFalse(hasattr(new_node, "__foo"))
  
imports: import ast
  import collections
  import textwrap
  import gast
  from tensorflow.python.autograph.pyct import anno
  from tensorflow.python.autograph.pyct import ast_util
  from tensorflow.python.autograph.pyct import loader
  from tensorflow.python.autograph.pyct import parser
  from tensorflow.python.autograph.pyct import pretty_printer
  from tensorflow.python.autograph.pyct import qual_names
  from tensorflow.python.platform import test
label_desc: Use image node_id 9 for calling the AstUtilTest obj's underlying member method code with example usage: obj.test_copy_clean() without return types