code: def nb_cols_design_matrix():
      return 3
  
imports: import json
  import os
  import numpy
  import pandas
  import pytest
  from nilearn._utils.data_gen import add_metadata_to_bids_dataset, create_fake_bids_dataset, generate_fake_fmri_data_and_design
  from nilearn.glm.first_level import FirstLevelModel
  from nilearn.glm.second_level import SecondLevelModel
  from nilearn.interfaces.bids import get_bids_files, parse_bids_filename, save_glm_to_bids
  from nilearn.interfaces.bids.query import _get_metadata_from_bids, infer_repetition_time_from_dataset, infer_slice_timing_start_time_from_dataset
  from nilearn.maskers import NiftiMasker
label_desc: Use image node_id 10 for calling a global function with example usage: nb_cols_design_matrix() and returns: int