code: def test_cfar_alpha(dtype):
      N = 128
      pfa = testing.shaped_random((128, 128), xp=cupy, dtype=dtype)
      gpu = signal.cfar_alpha(pfa, N)
      cpu = N * (pfa ** (-1.0 / N) - 1)
      cupy.testing.assert_allclose(gpu, cpu)
  
file_path: cupy/tests/cupyx_tests/signal_tests/radartools_tests/test_radartools.py
imports: import numpy
  import pytest
  import cupy
  from cupy import testing
  from cupyx import signal
label_desc: Use image node_id 6 for calling a global function with example usage: test_cfar_alpha(dtype) without return types