code: def testPruneCustomNonPrunableLayer(self):
      with self.assertRaises(ValueError):
          prune.prune_low_magnitude(
              self.custom_non_prunable_layer, **self.params
          )
  
imports: import json
  import tempfile
  import numpy
  import tensorflow
  from tensorflow_model_optimization.python.core.keras import test_utils
  from tensorflow_model_optimization.python.core.sparsity.keras import prunable_layer
  from tensorflow_model_optimization.python.core.sparsity.keras import prune
  from tensorflow_model_optimization.python.core.sparsity.keras import pruning_schedule
  from tensorflow_model_optimization.python.core.sparsity.keras import pruning_wrapper
label_desc: Use image node_id 9 for calling the PruneTest obj's underlying member method code with example usage: obj.testPruneCustomNonPrunableLayer() without return types