code: def test_himmelblau_output(x):
      """Tests himmelblau function output."""
      assert np.isclose(fx.himmelblau(x), np.zeros(4)).all()
  
imports: from collections import namedtuple
  import numpy
  import pytest
  from pyswarms.utils.functions import single_obj
label_desc: Use image node_id 9 for calling a global function with example usage: test_himmelblau_output(x) without return types