code: def test_triple_integral(self):
      # 9) Triple Integral test
      def simpfunc(z, y, x, t):  # Note order of arguments.
          return (x + y + z) * t
  
      a, b = 1.0, 2.0
      assert_quad(
          tplquad(
              simpfunc,
              a,
              b,
              lambda x: x,
              lambda x: 2 * x,
              lambda x, y: x - y,
              lambda x, y: x + y,
              (2.0,),
          ),
          2 * 8 / 3.0 * (b**4.0 - a**4.0),
      )
  
imports: import sys
  import math
  import numpy
  from numpy import sqrt, cos, sin, arctan, exp, log, pi
  from numpy.testing import assert_, assert_allclose, assert_array_less, assert_almost_equal
  import pytest
  from scipy.integrate import quad, dblquad, tplquad, nquad
  from scipy.special import erf, erfc
  from scipy._lib._ccallback import LowLevelCallable
  import ctypes
  import ctypes.util
  from scipy._lib._ccallback_c import sine_ctypes
  import scipy.integrate._test_multivariate
label_desc: Use image node_id 17 for calling the TestQuad obj's underlying member method code with example usage: obj.test_triple_integral() and returns: unknown