code: def _assert_weight_quantizers(self, quantizer_list):
      for quantizer in quantizer_list:
          self.assertIsInstance(
              quantizer, quantizers.LastValueQuantizer
          )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import unittest
  from absl.testing import parameterized
  import numpy
  import tensorflow
  from tensorflow_model_optimization.python.core.quantization.keras import quantizers
  from tensorflow_model_optimization.python.core.quantization.keras import utils
  from tensorflow_model_optimization.python.core.quantization.keras.experimental.default_n_bit import default_n_bit_quantize_registry
label_desc: Use image node_id 2 for calling the _TestHelper obj's underlying member method code with example usage: obj._assert_weight_quantizers(quantizer_list) without return types