code: def test_pbwa_nan():
      # Check that NaN's are returned outside of the range in which the
      # implementation is accurate.
      pts = [(-6, -6), (-6, 6), (6, -6), (6, 6)]
      for p in pts:
          assert_equal(sc.pbwa(*p), (np.nan, np.nan))
  
imports: import numpy
  from numpy.testing import assert_allclose, assert_equal
  import scipy.special
label_desc: Use image node_id 2 for calling a global function with example usage: test_pbwa_nan() without return types