code: def test_order_starting_cond(
      self, size, order, in_dtype, const_dtype, xp, scp
  ):
      out_dtype = xp.result_type(in_dtype, const_dtype)
      if xp.dtype(out_dtype).kind in {"i", "u"}:
          pytest.skip()
  
      x_scale = 0.5 if xp.dtype(in_dtype).kind not in {"i", "u"} else 1
      c_scale = (
          0.2 if xp.dtype(const_dtype).kind not in {"i", "u"} else 1
      )
  
      x = testing.shaped_random((size,), xp, in_dtype, scale=x_scale)
      a = testing.shaped_random(
          (order,), xp, dtype=const_dtype, scale=c_scale
      )
      a = xp.r_[1, a]
      a = a.astype(const_dtype)
      zi = testing.shaped_random((order,), xp, dtype=in_dtype)
      res = None
      if xp is cupy:
          const_dtype = xp.dtype(const_dtype)
          if const_dtype.kind == "u":
              const_dtype = xp.dtype(const_dtype.char.lower())
              a = a.astype(const_dtype)
          res = apply_iir(
              x, -a[1:], zi=zi, dtype=out_dtype, block_sz=32
          )
      else:
          b = xp.ones([1], dtype=const_dtype)
          zi = scp.signal.lfiltic(b, a, zi[::-1])
          res, _ = scp.signal.lfilter(b, a, x, zi=zi)
  
      res = xp.nan_to_num(res, nan=xp.nan, posinf=xp.nan, neginf=xp.nan)
      return res
  
file_path: cupy/tests/cupyx_tests/scipy_tests/signal_tests/test_iir_utils.py
imports: import pytest
  import cupy
  from cupy.cuda import driver
  from cupy.cuda import runtime
  from cupy import testing
  from cupyx.scipy.signal._iir_utils import apply_iir, apply_iir_sos
label_desc: Use image node_id 5 for calling the TestIIRUtils obj's underlying member method code with example usage: obj.test_order_starting_cond(size, order, in_dtype, const_dtype, xp, scp) and returns: res