code: def test_scale_bounded(self):
      num_outputs = 1
      # Set scale_lb and scale_ub to 1 and verify this is obeyed.
      initial_state, update = pop_art.popart(
          num_outputs, step_size=1e-1, scale_lb=1.0, scale_ub=1.0
      )
      state = initial_state()
      params = get_constant_linear_params(num_outputs)
      targets = np.ones((4, 2))
      indices = np.zeros((4, 2), dtype=np.int32)
      for _ in range(4):
          _, state = update(params, state, targets, indices)
          self.assertAlmostEqual(float(state.scale[0]), 1.0)
  
imports: import functools
  from absl.testing import absltest
  from absl.testing import parameterized
  import chex
  import haiku
  from haiku import data_structures
  from haiku import initializers
  import jax
  import jax.nn
  import jax.numpy
  import numpy
  from rlax._src import pop_art
label_desc: Use image node_id 6 for calling the PopArtTest obj's underlying member method code with example usage: obj.test_scale_bounded() without return types