code: def test_select_samples(self):
      # select_samples should return 5 separate random numbers.
      limits = np.arange(12.0, dtype="float64").reshape(2, 6)
      bounds = list(zip(limits[0, :], limits[1, :]))
      solver = DifferentialEvolutionSolver(None, bounds, popsize=1)
      candidate = 0
      r1, r2, r3, r4, r5 = solver._select_samples(candidate, 5)
      assert_equal(
          len(np.unique(np.array([candidate, r1, r2, r3, r4, r5]))), 6
      )
  
imports: import multiprocessing
  import platform
  from scipy.optimize._differentialevolution import DifferentialEvolutionSolver, _ConstraintWrapper
  from scipy.optimize import differential_evolution
  from scipy.optimize._constraints import Bounds, NonlinearConstraint, LinearConstraint
  from scipy.optimize import rosen
  from scipy.sparse import csr_matrix
  from scipy._lib._pep440 import Version
  import numpy
  from numpy.testing import assert_equal, assert_allclose, assert_almost_equal, assert_array_equal, assert_string_equal, assert_, suppress_warnings
  from pytest import raises, warns
  import pytest
label_desc: Use image node_id 20 for calling the TestDifferentialEvolutionSolver obj's underlying member method code with example usage: obj.test_select_samples() without return types