code: def test_loss_gradient(self):
      grad = self.art_model.loss_gradient(
          self.x_test_diabetes[:4], self.y_test_diabetes[:4]
      )
      for row in grad:
          if not np.all((row == 0)):
              np.testing.assert_equal(len(np.unique(row)), 10)
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import logging
  import unittest
  import numpy
  from art.estimators.regression.keras import KerasRegressor
  from tests.utils import TestBase, master_seed, get_tabular_regressor_kr
label_desc: Use image node_id 9 for calling the TestKerasRegressorClass obj's underlying member method code with example usage: obj.test_loss_gradient() without return types