code: def test_python_none_parameter(self, xp, dtype):
      @cupy.fuse()
      def f(x, y, z):
          if y is None:
              return x * z
          return x + y + z
  
      x = testing.shaped_arange((10,), xp, dtype)
      y = testing.shaped_arange((10,), xp, dtype)
      z = testing.shaped_arange((10,), xp, dtype)
      return f(x, None, z) + f(x, y, z)
  
imports: import threading
  import unittest
  from unittest import mock
  import pytest
  import cupy
  from cupy import testing
  from cupy_tests.core_tests.fusion_tests import fusion_utils
label_desc: Use image node_id 1 for calling the TestFusionNoneParams obj's underlying member method code with example usage: obj.test_python_none_parameter(xp, dtype) and returns: unknown, unknown, unknown