code: def test_domain(self, a, x):
      assert cp.isnan(sc.gammainc(a, x))
  
imports: import cupy
  import pytest
  import cupyx.scipy.special
  from cupy.testing import assert_allclose, assert_array_equal
label_desc: Use image node_id 1 for calling the TestGammainc obj's underlying member method code with example usage: obj.test_domain(a, x) without return types