code: def test_deferred_updating(self):
      # check setting of deferred updating, with default workers
      bounds = [(0.0, 2.0), (0.0, 2.0), (0, 2), (0, 2)]
      solver = DifferentialEvolutionSolver(
          rosen, bounds, updating="deferred"
      )
      assert_(solver._updating == "deferred")
      assert_(solver._mapwrapper._mapfunc is map)
      solver.solve()
  
imports: import multiprocessing
  from scipy.optimize import _differentialevolution
  from scipy.optimize._differentialevolution import DifferentialEvolutionSolver
  from scipy.optimize import differential_evolution
  import numpy
  from scipy.optimize import rosen
  from numpy.testing import assert_equal, assert_allclose, assert_almost_equal, assert_string_equal, assert_
  from pytest import raises, warns
label_desc: Use image node_id 34 for calling the TestDifferentialEvolutionSolver obj's underlying member method code with example usage: obj.test_deferred_updating() without return types