code: def test_dtypes(self, dtype):
      # make sure that all input precisions are accepted
      x = random(30).astype(dtype)
      assert_array_almost_equal(fft.ifft(fft.fft(x)), x)
      assert_array_almost_equal(fft.irfft(fft.rfft(x)), x)
      assert_array_almost_equal(fft.hfft(fft.ihfft(x), len(x)), x)
  
imports: import queue
  import threading
  import multiprocessing
  import numpy
  import pytest
  from numpy.random import random
  from numpy.testing import assert_array_almost_equal, assert_array_equal, assert_allclose
  from pytest import raises
  import scipy.fft
label_desc: Use image node_id 23 for calling the TestFFT1D obj's underlying member method code with example usage: obj.test_dtypes(dtype) without return types