code: def define_cross_validation():
      # Define cross validation
      cv = KFold(n_splits=4)
      n_jobs = 1
      return cv, n_jobs
  
file_path: nilearn/nilearn/decoding/tests/test_searchlight.py
imports: import numpy
  from nibabel import Nifti1Image
  from sklearn.model_selection import KFold
  from nilearn.conftest import _rng
  from nilearn.decoding import searchlight
label_desc: Use image node_id 2 for calling a global function with example usage: define_cross_validation() and returns: cv,  n_jobs