code: def test_init(db):
      dft.clear_cache()
      dft.update_cache(data_dir)
      # Verify a second update doesn't crash
      dft.update_cache(data_dir)
  
imports: import os
  import sqlite3
  from io import BytesIO
  from os.path import dirname
  from os.path import join
  from ..testing import suppress_warnings
  import unittest
  import pytest
  from ..None import nifti1
  from ..optpkg import optional_package
label_desc: Use image node_id 3 for calling a global function with example usage: test_init(db) without return types