class_docstr: To run: "python -m saliency.core.gradients_test" from the top-level directory.
code: def create_call_model_function(self):
      def call_model(
          x_value_batch, call_model_args=None, expected_keys=None
      ):
          call_model.num_calls += 1
          data = np.apply_along_axis(self.gradient_fn, 1, x_value_batch)
          return {INPUT_OUTPUT_GRADIENTS: data}
  
      call_model.num_calls = 0
  
      return call_model
  
file_path: saliency/saliency/core/gradients_test.py
imports: import unittest
  import unittest.mock
  from .base import INPUT_OUTPUT_GRADIENTS
  from .base import SHAPE_ERROR_MESSAGE
  from .None import gradients
  import numpy
label_desc: Use image node_id 2 for calling the GradientSaliencyTest obj's underlying member method code with example usage: obj.create_call_model_function() and returns: call_model, dict