code: def test_inverse_scalar_arguments(self, xp, scp):
      b, a = scp.signal.invres(1, 1, 1)
      return b, a
  
imports: import numpy
  import pytest
  import cupy
  from cupy import testing
  import cupyx.scipy.signal
label_desc: Use image node_id 16 for calling the TestPartialFractionExpansion obj's underlying member method code with example usage: obj.test_inverse_scalar_arguments(xp, scp) and returns: b,  a