code: def test_mixup(self):
      def eval_loss(l, count=1000):
          with tf.Session() as sess:
              vl = np.zeros(2, "f")
              for _ in range(count):
                  vl += sess.run(
                      l, feed_dict={self.x: self.vx, self.y: self.vy}
                  )
          return vl / count
  
      loss = MixUp(self.model, beta=1.0)
      vl = eval_loss(loss.fprop(self.x, self.y))
      self.assertClose(vl, [1.23, 1.23], atol=5e-2)
  
      loss = MixUp(self.model, beta=0.5)
      vl = eval_loss(loss.fprop(self.x, self.y))
      self.assertClose(vl, [1.40, 1.40], atol=5e-2)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import unittest
  import numpy
  import tensorflow
  from cleverhans.attacks import FastGradientMethod
  from cleverhans.loss import CrossEntropy, MixUp, FeaturePairing
  from cleverhans.devtools.checks import CleverHansTest
  from cleverhans.model import Model
label_desc: Use image node_id 4 for calling the TestDefenses obj's underlying member method code with example usage: obj.test_mixup() and returns: unknown