code: def test_residue_leading_zeros(self, xp, scp, ba):
      # Leading zeros in numerator or denominator must not affect the answer.
      ba = map(xp.asarray, ba)
      r0, p0, k0 = scp.signal.residue(*ba)
      return r0, p0, k0
  
imports: import numpy
  import pytest
  import cupy
  from cupy import testing
  import cupyx.scipy.signal
label_desc: Use image node_id 4 for calling the TestPartialFractionExpansion obj's underlying member method code with example usage: obj.test_residue_leading_zeros(xp, scp, ba) and returns: r0,  p0,  k0