code: def test_add_layer() -> None:
      x = ng.p.Scalar() - 4.0
      y = 6 + x
      assert y.value == 2
  
imports: import pytest
  import numpy
  import nevergrad
  from nevergrad.common import testing
  import nevergrad.common.typing
  from .None import _datalayers
  from .None import helpers
label_desc: Use image node_id 4 for calling a global function with example usage: test_add_layer() without return types