code: def test_multivariate(tmp_path, dd=data_dict):
      dd = dd.copy()
  
      dd["multivariate_pattern"] = True
      dd["different_ROIs"] = False
  
      # Make the signal large
      dd["scale_percentage"] = 100
  
      # Run the simulation
      gen.generate_data(str(tmp_path), dd)
  
      # Load in the ROI masks
      ROI_A = dd["ROI_A_file"]
      ROI_B = dd["ROI_B_file"]
  
      # Test this volume
      vol = np.load(str(tmp_path / "rt_007.npy"))
  
      ROI_A_std = np.std(vol[ROI_A == 1])
      ROI_B_std = np.std(vol[ROI_B == 1])
  
      assert (
          ROI_A_std > ROI_B_std
      ), "Multivariate not making variable signal"
  
file_path: brainiak/tests/utils/test_fmrisim_real_time.py
imports: import numpy
  from brainiak.utils import fmrisim_real_time_generator
  import pytest
  import os
  import time
  import glob
  from pkg_resources import resource_stream
  from typing import Dict
  from nibabel.nifti1 import Nifti1Image
  import gzip
label_desc: Use image node_id 3 for calling a global function with example usage: test_multivariate(tmp_path, dd) without return types