code: def test_train_with_weights(self, backend):
      with fastmath.use_backend(backend):
          # Prepare model and inputs
          n_classes = 4
          steps = 2
          eval_steps = 2
          model_fn = functools.partial(
              models.MLP, layer_widths=(16, 16, n_classes)
          )
          inputs = _test_inputs(n_classes, with_weights=True)
  
          # Train and evaluate
          output_dir = self.create_tempdir().full_path
          state = trainer_lib.train(
              output_dir,
              model=model_fn,
              inputs=inputs,
              steps=steps,
              eval_steps=eval_steps,
          )
  
          # Assert total train steps
          self.assertEqual(state.step, steps)
  
imports: import functools
  import os
  from absl.testing import absltest
  from absl.testing import parameterized
  import jax
  from jax import config
  import tensorflow.compat.v2
  from trax import fastmath
  from trax import layers
  from trax import models
  from trax import optimizers
  from trax import shapes
  from trax import test_utils
  from trax.data import inputs
  from trax.fastmath import numpy
  from trax.supervised import lr_schedules
  from trax.supervised import trainer_lib
  from trax.tf_numpy import extensions
  from trax.tf_numpy import numpy
label_desc: Use image node_id 13 for calling the TraxTest obj's underlying member method code with example usage: obj.test_train_with_weights(backend) without return types