code: def test_check_cache():
      """[Base] Test check cache."""
      tmp = config.get_prefix() + "test"
      os.mkdir(tmp)
      with open(os.devnull, "w") as f, redirect_stderr(f):
          subprocess.Popen(
              "echo this is a test >> " + tmp + "/test.txt", shell=True
          )
          config.clear_cache(config.get_tmpdir())
  
imports: import os
  import subprocess
  import numpy
  from mlens import config
  from mlens.utils import IdTrain
  from mlens.index import FoldIndex, BlendIndex, SubsetIndex, TemporalIndex, ClusteredSubsetIndex, FullIndex
  from mlens.index.base import partition, prune_train
label_desc: Use image node_id 2 for calling a global function with example usage: test_check_cache() without return types