code: def test_docstring_example(self):
      @tff.utils.dataclass
      class Coords:
          x: tf.Tensor
          y: tf.Tensor
  
      @tf.function
      def fn(start_coords: Coords) -> Coords:
          def cond(it, _):
              return it < 10
  
          def body(it, coords):
              return it + 1, Coords(x=coords.x + 1, y=coords.y + 2)
  
          return tf.while_loop(cond, body, loop_vars=(0, start_coords))[
              1
          ]
  
      start_coords = Coords(x=tf.constant(0), y=tf.constant(0))
      end_coords = fn(start_coords)
      with self.subTest("OutputType"):
          self.assertIsInstance(end_coords, Coords)
      end_coords_eval = self.evaluate(end_coords)
      with self.subTest("FirstValue"):
          self.assertEqual(end_coords_eval.x, 10)
      with self.subTest("SecondValue"):
          self.assertEqual(end_coords_eval.y, 20)
  
imports: import tensorflow.compat.v2
  import tf_quant_finance
  from tensorflow.python.framework import test_util
label_desc: Use image node_id 1 for calling the DataclassTest obj's underlying member method code with example usage: obj.test_docstring_example() and returns: tf, unknown, unknown,  Coords