code: def test_cosine_weighted_infinite(self):
      # 6) Cosine weighted integral (negative infinite limits)
      def myfunc(x, a):
          return exp(x * a)
  
      a = 2.5
      ome = 2.3
      assert_quad(
          quad(myfunc, -np.inf, 0, args=a, weight="cos", wvar=ome),
          a / (a**2 + ome**2),
      )
  
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 6 for calling the TestQuad obj's underlying member method code with example usage: obj.test_cosine_weighted_infinite() and returns: exp