code: def test_pickle(self, dtype):
      a = testing.shaped_arange((2, 3, 4), dtype=dtype)
      s = pickle.dumps(a)
      b = pickle.loads(s)
      testing.assert_array_equal(a, b)
  
file_path: cupy/tests/cupy_tests/io_tests/test_npz.py
imports: import io
  import pickle
  import unittest
  import cupy
  from cupy import testing
label_desc: Use image node_id 7 for calling the TestNpz obj's underlying member method code with example usage: obj.test_pickle(dtype) without return types