code: def test_crossover() -> None:
      data = [0.1, -0.1, 1, -0.1]
      rng = np.random.RandomState(15)
      output = Mutator(rng).crossover(data, 2 * np.array(data))
      np.testing.assert_almost_equal(
          output, [-1.1, -0.1, 2, -0.1], decimal=2
      )
  
file_path: nevergrad/nevergrad/optimization/test_mutations.py
imports: import typing
  import numpy
  import nevergrad
  from nevergrad.common import testing
  from .None import utils
  from .mutations import Mutator
  from .differentialevolution import Crossover
label_desc: Use image node_id 3 for calling a global function with example usage: test_crossover() without return types