code: def test_crossover(fft: bool, expected: tp.List[int]) -> None:
      x1 = 4 * np.ones((2, 4))
      x2 = (
          5 * np.ones((2, 4))
          if not fft
          else np.arange(8).reshape((2, 4))
      )
      array = mutation.Crossover(axis=1, fft=fft)(Array(init=x1))
      co = array._layers[1]
      assert isinstance(co, mutation.Crossover)
      co.random_state.seed(12)
      out = co._apply_array((x1, x2))
      expected_arr = np.ones((2, 1)).dot([expected])
      np.testing.assert_array_equal(out, expected_arr)
  
file_path: nevergrad/nevergrad/parametrization/test_mutation.py
imports: import typing
  import numpy
  from nevergrad.common import testing
  from .None import mutation
  from .data import Array
label_desc: Use image node_id 1 for calling a global function with example usage: test_crossover(fft, expected) without return types