code: def test_dct_backend(self, xp, dtype):
      backend = "scipy" if xp is np else cp_fft
      with scipy_fft.set_backend(backend):
          fft_func = getattr(scipy_fft, self.function)
          r = xp.logspace(-2, 2, 10)
          dln = xp.log(r[1] / r[0])
          return fft_func(r, dln, mu=0.5)
  
imports: import numpy
  import cupy
  import cupyx.scipy.fft
  from cupy import testing
label_desc: Use image node_id 1 for calling the TestFftlogScipyBackend obj's underlying member method code with example usage: obj.test_dct_backend(xp, dtype) and returns: fft_func