code: def test_input_layer(self):
      np.testing.assert_equal(
          isinstance(self.art_model.input_layer, int), True
      )
  
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 6 for calling the TestKerasRegressor obj's underlying member method code with example usage: obj.test_input_layer() without return types