code: def test_acquisition_function(self):
      self.mock_model.predict.return_value = (1, 3)
      self.mock_model.get_fmin.return_value = 0.1
  
      weighted_acquisition = self.mpi_acquisition.acquisition_function(
          np.array([2, 2])
      )
  
      expected_acquisition = np.array([[-0.38081792], [-0.38081792]])
      self.assertTrue(
          np.isclose(weighted_acquisition, expected_acquisition).all()
      )
  
file_path: GPyOpt/GPyOpt/testing/acquisitions_tests/test_mpi_acquisition.py
imports: import unittest
  from mock import Mock
  import numpy
  from GPyOpt.acquisitions import AcquisitionMPI
  from GPyOpt.core.task.space import Design_space
label_desc: Use image node_id 2 for calling the TestMPIAcquisition obj's underlying member method code with example usage: obj.test_acquisition_function() without return types