code: def test_logsumexp_sign_zero():
      a = [1, 1]
      b = [1, -1]
  
      r, s = logsumexp(a, b=b, return_sign=True)
      assert_(not np.isfinite(r))
      assert_(not np.isnan(r))
      assert_(r < 0)
      assert_equal(s, 0)
  
file_path: scipy/scipy/special/tests/test_logsumexp.py
imports: import numpy
  from numpy.testing import assert_almost_equal, assert_equal, assert_allclose, assert_array_almost_equal, assert_
  from scipy.special import logsumexp, softmax
label_desc: Use image node_id 4 for calling a global function with example usage: test_logsumexp_sign_zero() without return types