code: def test_placeholder(self):
      with self.test_session() as sess:
          x = tf.placeholder(tf.float32, name="CustomName")
          y = tf.constant(3.0)
          z = x * y
          z_new = ed.copy(z)
          self.assertEqual(sess.run(z_new, feed_dict={x: 4.0}), 12.0)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import edward
  import numpy
  import tensorflow
  from edward.models import Bernoulli, Categorical, Mixture, Normal
label_desc: Use image node_id 5 for calling the test_copy_class obj's underlying member method code with example usage: obj.test_placeholder() without return types