code: def test_different_dtypes_fail(self):
      in_shape = self.input_shapes["2d"]
      out_shape = self.output_shapes["2d"]
  
      axes = (-1,)
      a, b = self.create_test_arrays(in_shape, out_shape)
  
      a_ = numpy.complex64(a)
      b_ = numpy.complex128(b)
      self.assertRaisesRegex(
          ValueError, "Invalid scheme", FFTW, *(a_, b_)
      )
  
      a_ = numpy.complex128(a)
      b_ = numpy.complex64(b)
      self.assertRaisesRegex(
          ValueError, "Invalid scheme", FFTW, *(a_, b_)
      )
  
imports: from pyfftw import FFTW, byte_align, empty_aligned, forget_wisdom
  import pyfftw
  import numpy
  from timeit import Timer
  import time
  import unittest
  from .test_pyfftw_base import FFTWBaseTest, run_test_suites, miss, np_fft
label_desc: Use image node_id 20 for calling the Complex64FFTW1DTest obj's underlying member method code with example usage: obj.test_different_dtypes_fail() without return types