code: def test_expr_contains(self):
      expr = (
          "#Add",
          ("#Mul", (1.5, ("#CPow1.2000e+00", ("#x",)))),
          ("#Mul", (1.2,), (7,)),
      )
      self.assertTrue(expr_contains(expr, "#x"))
      self.assertFalse(expr_contains(expr, "#CPow"))
      self.assertTrue(expr_contains(expr, "#CPow1.2000e+00"))
      self.assertTrue(expr_contains(expr, "#Mul"))
      self.assertTrue(expr_contains(expr, "#Add"))
      self.assertTrue(expr_contains(expr[1], "#x"))
      self.assertFalse(expr_contains(expr[2], "#x"))
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import edward
  import numpy
  import tensorflow
  from edward.inferences.conjugacy.simplify import *
  from edward.inferences.conjugacy.simplify import _mul_n
label_desc: Use image node_id 17 for calling the test_simplify_class obj's underlying member method code with example usage: obj.test_expr_contains() without return types