code: def test_vol_tol(self, vol_tol, locally_biased):
      bounds = 4 * [(-10.0, 10.0)]
      res = direct(
          self.sphere,
          bounds=bounds,
          vol_tol=vol_tol,
          len_tol=0.0,
          locally_biased=locally_biased,
      )
      assert res.status == 4
      assert res.success
      assert_allclose(res.x, np.zeros((4,)))
      message = (
          "The volume of the hyperrectangle containing the lowest "
          f"function value found is below vol_tol={vol_tol}"
      )
      assert res.message == message
  
imports: from numpy.testing import assert_allclose, assert_array_less
  import pytest
  import numpy
  from scipy.optimize import direct, Bounds
label_desc: Use image node_id 12 for calling the TestDIRECT obj's underlying member method code with example usage: obj.test_vol_tol(vol_tol, locally_biased) without return types