code: def test_rejects_callable():
      """test_rejects_callable: Check that callables are not accepted as models"""
  
      def model(x):
          """Mock model"""
          return x
  
      sess = tf.Session()
      assert_raises(TypeError, ProjectedGradientDescent, model, sess)
  
file_path: cleverhans/cleverhans_v3.1.0/tests_tf/test_projected_gradient_descent.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from nose.tools import assert_raises
  import tensorflow
  from cleverhans.attacks import ProjectedGradientDescent
  from cleverhans.model import Model
label_desc: Use image node_id 2 for calling a global function with example usage: test_rejects_callable() and returns: x