code: def test_concatenate_axis_none(self, xp, dtype):
      a = testing.shaped_arange((2, 3), xp, dtype)
      b = testing.shaped_reverse_arange((3, 5, 2), xp, dtype)
      c = testing.shaped_arange((7,), xp, dtype)
      return xp.concatenate((a, b, c), axis=None)
  
imports: import numpy
  import pytest
  import cupy
  from cupy import testing
  from cupy import cuda
label_desc: Use image node_id 7 for calling the TestJoin obj's underlying member method code with example usage: obj.test_concatenate_axis_none(xp, dtype) and returns: xp