code: def test_chi2sf():
      xlist = np.linspace(0, 100, 500)
      slist = np.arange(1, 41, 1.5)
      for s, x in itertools.product(slist, xlist):
          assert_close(scipy.stats.chi2.sf(x, s), chi2sf(x, s))
  
imports: import itertools
  import numpy
  import scipy
  from pyro.distributions.testing.special import chi2sf
  from tests.common import assert_close
label_desc: Use image node_id 1 for calling a global function with example usage: test_chi2sf() without return types