code: def test_compute_delta(self):
      fixture = np.arange(2, 10)
      output = [_compute_delta(f) for f in fixture]
      desired = np.array(
          [1.0, 0.75, 0.666667, 0.625, 0.6, 0.583333, 0.571429, 0.5625]
      )
      assert_allclose(output, desired, rtol=1e-2)
  
imports: from numpy.testing import assert_equal, assert_allclose
  from pytest import raises, fixture, warns, mark
  import numpy
  import warnings
  from SALib.sample.morris.morris import sample, _check_group_membership, _check_if_num_levels_is_even, _compute_optimised_trajectories, _generate_p_star, _compute_b_star, _generate_trajectory, _generate_x_star
  from SALib.util import read_param_file, compute_groups_matrix, _define_problem_with_groups, _compute_delta
label_desc: Use image node_id 2 for calling the TestGroupSampleGeneration obj's underlying member method code with example usage: obj.test_compute_delta() without return types