code: def test_basic_IIR(self, xp, scp):
      x = xp.arange(12)
      y = scp.signal.decimate(
          x, 2, n=1, ftype="iir", zero_phase=False
      ).round()
      return y
  
imports: import cupy
  from cupy import testing
  import cupyx.scipy.signal
  import cupyx.scipy.signal.windows
  import numpy
  import pytest
  from math import gcd
label_desc: Use image node_id 2 for calling the TestDecimate obj's underlying member method code with example usage: obj.test_basic_IIR(xp, scp) and returns: y