code: def test_signal_extr_shared(self):
      # set up
      wanted = []
      for vol in range(self.fake_fmri_data.shape[3]):
          volume = self.fake_fmri_data[:, :, :, vol].flatten()
          wanted_row = []
          for reg in range(self.fake_4d_label_data.shape[3]):
              region = self.fake_4d_label_data[:, :, :, reg].flatten()
              wanted_row.append(
                  (volume * region).sum() / (region * region).sum()
              )
  
          wanted.append(wanted_row)
      # run & assert
      self._test_4d_label(wanted, self.fake_4d_label_data)
  
file_path: nipype/nipype/interfaces/tests/test_nilearn.py
imports: import os
  import numpy
  from ...testing import utils
  from ..None import nilearn
  from ...pipeline import engine
  import pytest
  import numpy.testing
label_desc: Use image node_id 8 for calling the TestSignalExtraction obj's underlying member method code with example usage: obj.test_signal_extr_shared() without return types