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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def noise_op(latents, hparams):
 """Adds isotropic gaussian-noise to each latent. Args: latents: 4-D or 5-D tensor, shape=(NTHWC) or (NHWC). hparams: HParams. Returns: latents: latents with isotropic gaussian noise appended. """

  if hparams.latent_noise == 0 or hparams.mode != tf.estimator.ModeKeys.TRAIN:
    return latents
  latent_shape = common_layers.shape_list(latents)
  return latents + tf.random_normal(latent_shape, stddev=hparams.latent_noise)