code: def test_variable_limits(self):
      scale = 0.1
  
      def func2(x0, x1, x2, x3, t0, t1):
          val = (
              x0 * x1 * x3**2
              + np.sin(x2)
              + 1
              + (1 if x0 + t1 * x1 - t0 > 0 else 0)
          )
          return val
  
      def lim0(x1, x2, x3, t0, t1):
          return [
              scale * (x1**2 + x2 + np.cos(x3) * t0 * t1 + 1) - 1,
              scale * (x1**2 + x2 + np.cos(x3) * t0 * t1 + 1) + 1,
          ]
  
      def lim1(x2, x3, t0, t1):
          return [
              scale * (t0 * x2 + t1 * x3) - 1,
              scale * (t0 * x2 + t1 * x3) + 1,
          ]
  
      def lim2(x3, t0, t1):
          return [
              scale * (x3 + t0**2 * t1**3) - 1,
              scale * (x3 + t0**2 * t1**3) + 1,
          ]
  
      def lim3(t0, t1):
          return [scale * (t0 + t1) - 1, scale * (t0 + t1) + 1]
  
      def opts0(x1, x2, x3, t0, t1):
          return {"points": [t0 - t1 * x1]}
  
      def opts1(x2, x3, t0, t1):
          return {}
  
      def opts2(x3, t0, t1):
          return {}
  
      def opts3(t0, t1):
          return {}
  
      res = nquad(
          func2,
          [lim0, lim1, lim2, lim3],
          args=(0, 0),
          opts=[opts0, opts1, opts2, opts3],
      )
      assert_quad(res, 25.066666666666663)
  
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 2 for calling the TestNQuad obj's underlying member method code with example usage: obj.test_variable_limits() and returns: val, list, list, list, list, dict, dict, dict, dict