code: def test_bool(self):
      tensor = keras_tensor.KerasTensor(shape=(3, 4), dtype="float32")
      with self.assertRaisesRegex(
          TypeError, "cannot be used as a boolean."
      ):
          bool(tensor)
  
imports: from unittest.mock import Mock
  from unittest.mock import patch
  import numpy
  import tensorflow
  from keras import backend
  from keras import ops
  from keras import testing
  from keras.backend.common import keras_tensor
label_desc: Use image node_id 4 for calling the KerasTensorTest obj's underlying member method code with example usage: obj.test_bool() without return types